os

An operating system
git clone https://erai.gay/code/os/
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x86_64.om (48315B)


      1 enum {
      2 	R_RAX,
      3 	R_RCX,
      4 	R_RDX,
      5 	R_RBX,
      6 	R_RSP,
      7 	R_RBP,
      8 	R_RSI,
      9 	R_RDI,
     10 	R_R8,
     11 	R_R9,
     12 	R_R10,
     13 	R_R11,
     14 	R_R12,
     15 	R_R13,
     16 	R_R14,
     17 	R_R15,
     18 	R_RIP,
     19 
     20 	R_ES = 0,
     21 	R_CS = 1,
     22 	R_SS = 2,
     23 	R_DS = 3,
     24 	R_FS = 4,
     25 	R_GS = 5,
     26 
     27 	R_CR0 = 0,
     28 	R_CR1 = 1,
     29 	R_CR2 = 2,
     30 	R_CR3 = 3,
     31 	R_CR4 = 4,
     32 	R_CR5 = 5,
     33 	R_CR6 = 6,
     34 	R_CR7 = 7,
     35 }
     36 
     37 enum {
     38 	CC_O = 0x00,
     39 	CC_NO = 0x01,
     40 	CC_B = 0x02,
     41 	CC_AE = 0x03,
     42 	CC_E = 0x04,
     43 	CC_NE = 0x05,
     44 	CC_BE = 0x06,
     45 	CC_A = 0x07,
     46 	CC_S = 0x08,
     47 	CC_NS = 0x09,
     48 	CC_P = 0x0a,
     49 	CC_NP = 0x0b,
     50 	CC_L = 0x0c,
     51 	CC_GE = 0x0d,
     52 	CC_LE = 0x0e,
     53 	CC_G = 0x0f,
     54 }
     55 
     56 enum {
     57 	OP_GS = 0x65,
     58 	OP_OS = 0x66,
     59 
     60 	OP_CLD = 0xfc,
     61 	OP_CLI = 0xfa,
     62 	OP_STI = 0xfb,
     63 	OP_CPUID = 0x0fa2,
     64 	OP_IN = 0xec,
     65 	OP_IND = 0xed,
     66 	OP_OUT = 0xee,
     67 	OP_OUTD = 0xef,
     68 	OP_HLT = 0xf4,
     69 	OP_NOP = 0x90,
     70 	OP_WBINVD = 0x0f09,
     71 	OP_UD2 = 0x0f0b,
     72 
     73 	OP_INVLPGM = 0x070f01,
     74 	OP_LLDM = 0x020f00,
     75 	OP_LTRM = 0x030f00,
     76 
     77 	OP_WRSR = 0x8e,
     78 	OP_RDSR = 0x8c,
     79 
     80 	OP_RET = 0xc3,
     81 	OP_CALL = 0xe8,
     82 	OP_JMP = 0xe9,
     83 	OP_JCC = 0x0f80,
     84 	OP_SETCC = 0x0f90,
     85 
     86 	OP_PUSHF = 0x9c,
     87 	OP_POPF = 0x9d,
     88 	OP_IRET = 0xcf,
     89 	OP_IRETQ = 0x48cf,
     90 	OP_WRMSR = 0x0f30,
     91 	OP_RDMSR = 0x0f32,
     92 	OP_RDCRR = 0x0f20,
     93 	OP_WRCRR = 0x0f22,
     94 	OP_LGDTM = 0x020f01,
     95 	OP_LIDTM = 0x030f01,
     96 	OP_LLDTM = 0x020f00,
     97 
     98 	OP_ICALLM = 0x0200ff,
     99 
    100 	OP_NOTM = 0x0200f7,
    101 	OP_NEGM = 0x0300f7,
    102 
    103 	OP_ANDRM = 0x23,
    104 	OP_ORRM = 0x0b,
    105 	OP_CMPRM = 0x3b,
    106 	OP_TESTRM = 0x85,
    107 	OP_SUBRM = 0x2b,
    108 	OP_ADDRM = 0x03,
    109 	OP_ADCRM = 0x13,
    110 	OP_XORRM = 0x33,
    111 
    112 	OP_ANDI = 0x040081,
    113 	OP_ADDI = 0x000081,
    114 	OP_SUBI = 0x050081,
    115 	OP_ORI = 0x010081,
    116 	OP_CMPI = 0x070081,
    117 
    118 	OP_RDRAND = 0x060fc7,
    119 
    120 	OP_IMULM = 0x0400f7,
    121 	OP_IDIVM = 0x0700f7,
    122 	OP_SHLM = 0x0400d3,
    123 	OP_SHRM = 0x0500d3,
    124 
    125 	OP_PUSHR = 0x50,
    126 
    127 	OP_POPR = 0x58,
    128 
    129 	OP_MOVI = 0x00c7,
    130 	OP_MOVABS = 0xb8,
    131 
    132 	OP_SYSCALL = 0x0f05,
    133 	OP_SYSRET = 0x0f07,
    134 
    135 	OP_LEA = 0x8d,
    136 	OP_LOAD = 0x8b,
    137 	OP_LOADB = 0x8a,
    138 	OP_LOAD16 = 0x668a,
    139 	OP_STOREB = 0x88,
    140 	OP_STORE = 0x89,
    141 	OP_STORE16 = 0x6689,
    142 	OP_MOVE = 0x8b,
    143 }
    144 
    145 func x86_64_rex(a: *assembler, op: int, r: int, i: int, b: int) {
    146 	var w: int;
    147 	if a.bits32 {
    148 		return;
    149 	}
    150 	w = 0x08;
    151 	if op == OP_LOADB || op == OP_STOREB {
    152 		w = 0;
    153 		if r < 8 && i < 8 && b < 8 {
    154 			return;
    155 		}
    156 	}
    157 	as_emit(a, 0x40 + w + ((r >> 1) & 4) + ((i >> 2) & 2) + ((b >> 3) & 1));
    158 }
    159 
    160 func x86_64_op(a: *assembler, op: int) {
    161 	if op > 0xff {
    162 		as_emit(a, op >> 8);
    163 		as_emit(a, op);
    164 	} else {
    165 		as_emit(a, op);
    166 	}
    167 }
    168 
    169 // op + r
    170 func x86_64_opr(a: *assembler, op: int, r: int) {
    171 	if r < 0 || r > 15 {
    172 		die("invalid reg");
    173 	}
    174 	if (op != OP_PUSHR && op != OP_POPR) || r > 7 {
    175 		x86_64_rex(a, op, r, 0, 0);
    176 	}
    177 	x86_64_op(a, op + (r & 7));
    178 }
    179 
    180 func x86_64_opri64(a: *assembler, op: int, r: int, x: int) {
    181 	if op != OP_MOVABS {
    182 		die("only movabs");
    183 	}
    184 	x86_64_opr(a, op, r);
    185 	as_emit(a, x);
    186 	as_emit(a, x >> 8);
    187 	as_emit(a, x >> 16);
    188 	as_emit(a, x >> 24);
    189 	as_emit(a, x >> 32);
    190 	as_emit(a, x >> 40);
    191 	as_emit(a, x >> 48);
    192 	as_emit(a, x >> 56);
    193 }
    194 
    195 // modrm
    196 func x86_64_modrr(a: *assembler, op: int, r: int, b: int) {
    197 	if r < 0 || r > 15 || b < 0 || b > 15 {
    198 		die("invalid reg");
    199 	}
    200 	if (op != (OP_ICALLM & 0xffff) && (op & -16) != OP_SETCC) || b >= 8 {
    201 		x86_64_rex(a, op, r, 0, b);
    202 	}
    203 	x86_64_op(a, op);
    204 	as_emit(a, 0xc0 + ((r << 3) & 0x38) + (b & 0x07));
    205 }
    206 
    207 // modrm /op
    208 func x86_64_modr(a: *assembler, op: int, b: int) {
    209 	x86_64_modrr(a, op & 0xffff, op >> 16, b);
    210 }
    211 
    212 // modrm + disp
    213 func x86_64_modra(a: *assembler, op: int, r: int, d: int) {
    214 	x86_64_rex(a, op, r, 0, 0);
    215 	x86_64_op(a, op);
    216 	as_emit(a, ((r << 3) & 0x38) + R_RSP);
    217 	as_emit(a, (R_RSP << 3) + R_RBP);
    218 	as_emit(a, d);
    219 	as_emit(a, d >> 8);
    220 	as_emit(a, d >> 16);
    221 	as_emit(a, d >> 24);
    222 }
    223 
    224 // modrm + sib + disp
    225 func x86_64_modrm(a: *assembler, op: int, r: int, b: int, i: int, s: int, d: int) {
    226 	var sib: int;
    227 	var mod: int;
    228 	var rm: int;
    229 	var dw: int;
    230 
    231 	if r < 0 || r > 15 {
    232 		die("invalid reg");
    233 	}
    234 
    235 	rm = (r << 3) & 0x38;
    236 
    237 	if d != 0 {
    238 		if d >= -128 && d <= 127 {
    239 			mod = 1;
    240 			dw = 1;
    241 		} else {
    242 			mod = 2;
    243 			dw = 4;
    244 		}
    245 	} else {
    246 		mod = 0;
    247 		dw = 0;
    248 	}
    249 
    250 	if mod == 0 {
    251 		if b < 0 || b > 16 {
    252 			die("invalid reg");
    253 		}
    254 
    255 		if s {
    256 			if b == R_RIP {
    257 				die("invalid base");
    258 			}
    259 
    260 			if i == R_RSP {
    261 				die("invalid index");
    262 			}
    263 
    264 			rm = rm + R_RSP;
    265 		} else {
    266 			if i != 0 {
    267 				die("invalid index");
    268 			}
    269 
    270 			if b == R_RIP {
    271 				mod = 0;
    272 				dw = 4;
    273 				rm = rm + R_RBP;
    274 			} else if b == R_RSP || b == R_R12 {
    275 				s = 1;
    276 				i = R_RSP;
    277 				rm = rm + R_RSP;
    278 			} else if b == R_RBP || b == R_R13 {
    279 				mod = 1;
    280 				dw = 1;
    281 				rm = rm + R_RBP;
    282 			} else {
    283 				rm = rm + (b & 7);
    284 			}
    285 		}
    286 	} else {
    287 		if b < 0 || b > 16 || i < 0 || i > 15 {
    288 			die("invalid reg");
    289 		}
    290 
    291 		if s {
    292 			if b == R_RIP {
    293 				die("invalid base");
    294 			}
    295 
    296 			if i == R_RSP {
    297 				die("invalid index");
    298 			}
    299 
    300 			rm = rm + R_RSP;
    301 		} else {
    302 			if i != 0 {
    303 				die("invalid index");
    304 			}
    305 
    306 			if b == R_RIP {
    307 				mod = 0;
    308 				dw = 4;
    309 				rm = rm + R_RBP;
    310 			} else if b == R_RSP || b == R_R12 {
    311 				s = 1;
    312 				i = R_RSP;
    313 				rm = rm + R_RSP;
    314 			} else {
    315 				rm = rm + (b & 7);
    316 			}
    317 		}
    318 	}
    319 
    320 	x86_64_rex(a, op, r, i, b);
    321 	x86_64_op(a, op);
    322 	as_emit(a, (mod << 6) + rm);
    323 
    324 	if s {
    325 		sib = ((i << 3) & 0x38) + (b & 0x07);
    326 		if s == 2 {
    327 			sib = sib + 0x40;
    328 		} else if s == 4 {
    329 			sib = sib + 0x80;
    330 		} else if s == 8 {
    331 			sib = sib + 0xc0;
    332 		} else if s != 1 {
    333 			die("invalid scale");
    334 		}
    335 		as_emit(a, sib);
    336 	}
    337 
    338 	if dw == 1 {
    339 		as_emit(a, d);
    340 	} else if dw == 4 {
    341 		as_emit(a, d);
    342 		as_emit(a, d >> 8);
    343 		as_emit(a, d >> 16);
    344 		as_emit(a, d >> 24);
    345 	}
    346 }
    347 
    348 // modrm /op
    349 func x86_64_modm(a: *assembler, op: int, b: int, i: int, s: int, d: int) {
    350 	x86_64_modrm(a, op & 0xffff, op >> 16, b, i, s, d);
    351 }
    352 
    353 func x86_64_modri(a: *assembler, op: int, r: int, x: int) {
    354 	if x < -(1 << 31) || x >= (1 << 31) {
    355 		die("immediate too large");
    356 	}
    357 	x86_64_modrr(a, op & 0xffff, op >> 16, r);
    358 	as_emit(a, x);
    359 	as_emit(a, x >> 8);
    360 	as_emit(a, x >> 16);
    361 	as_emit(a, x >> 24);
    362 }
    363 
    364 func x86_64_jmp(a: *assembler, op: int, l: *label) {
    365 	reserve(a, 16);
    366 	x86_64_op(a, op);
    367 	as_emit(a, 0);
    368 	as_emit(a, 0);
    369 	as_emit(a, 0);
    370 	as_emit(a, 0);
    371 	addfixup(a, l, FIXUP_DISP32);
    372 }
    373 
    374 func x86_64_ssr(c: *compiler) {
    375 	var d: *decl;
    376 	var v: *decl;
    377 
    378 	v = find(c, "global", "_save", 0);
    379 	if (!v || !v.member_defined) {
    380 		cdie(c, "no _save");
    381 	}
    382 
    383 	// Save the current stack
    384 	as_emit(c.s, OP_GS);
    385 	x86_64_modra(c.s, OP_STORE, R_RSP, v.member_offset);
    386 
    387 	v = find(c, "global", "curtask", 0);
    388 	if (!v || !v.member_defined) {
    389 		cdie(c, "no global.curtask");
    390 	}
    391 
    392 	// Load the current task
    393 	as_emit(c.s, OP_GS);
    394 	x86_64_modra(c.s, OP_LOAD, R_RSP, v.member_offset);
    395 
    396 	v = find(c, "task", "stack", 0);
    397 	if (!v || !v.member_defined) {
    398 		cdie(c, "no task.stack");
    399 	}
    400 
    401 	// Load the kernel stack but reserve some space for the regs struct
    402 	x86_64_modrm(c.s, OP_LOAD, R_RSP, R_RSP, 0, 0, v.member_offset);
    403 	x86_64_modri(c.s, OP_ADDI, R_RSP, 4096 - 176);
    404 
    405 	// Save general purpose registers
    406 	x86_64_modrm(c.s, OP_STORE, R_RAX, R_RSP, 0, 0, 0);
    407 	x86_64_modrm(c.s, OP_STORE, R_RDX, R_RSP, 0, 0, 16);
    408 	x86_64_modrm(c.s, OP_STORE, R_RBX, R_RSP, 0, 0, 24);
    409 	x86_64_modrm(c.s, OP_STORE, R_RBP, R_RSP, 0, 0, 40);
    410 	x86_64_modrm(c.s, OP_STORE, R_RSI, R_RSP, 0, 0, 48);
    411 	x86_64_modrm(c.s, OP_STORE, R_RDI, R_RSP, 0, 0, 56);
    412 	x86_64_modrm(c.s, OP_STORE, R_R8, R_RSP, 0, 0, 64);
    413 	x86_64_modrm(c.s, OP_STORE, R_R9, R_RSP, 0, 0, 72);
    414 	x86_64_modrm(c.s, OP_STORE, R_R10, R_RSP, 0, 0, 80);
    415 	x86_64_modrm(c.s, OP_STORE, R_R12, R_RSP, 0, 0, 96);
    416 	x86_64_modrm(c.s, OP_STORE, R_R13, R_RSP, 0, 0, 104);
    417 	x86_64_modrm(c.s, OP_STORE, R_R14, R_RSP, 0, 0, 112);
    418 	x86_64_modrm(c.s, OP_STORE, R_R15, R_RSP, 0, 0, 120);
    419 	x86_64_modrm(c.s, OP_STORE, R_RCX, R_RSP, 0, 0, 128);
    420 	x86_64_modrm(c.s, OP_STORE, R_R11, R_RSP, 0, 0, 136);
    421 
    422 	// Clear rcx, r11, trap, err
    423 	x86_64_modrr(c.s, OP_XORRM, R_RAX, R_RAX);
    424 	x86_64_modrm(c.s, OP_STORE, R_RAX, R_RSP, 0, 0, 8);
    425 	x86_64_modrm(c.s, OP_STORE, R_RAX, R_RSP, 0, 0, 88);
    426 	x86_64_modrm(c.s, OP_STORE, R_RAX, R_RSP, 0, 0, 160);
    427 	x86_64_modrm(c.s, OP_STORE, R_RAX, R_RSP, 0, 0, 168);
    428 
    429 	// Save cs and ds
    430 	x86_64_modri(c.s, OP_MOVI, R_RAX, 43);
    431 	x86_64_modrm(c.s, OP_STORE, R_RAX, R_RSP, 0, 0, 144);
    432 	x86_64_modri(c.s, OP_MOVI, R_RAX, 35);
    433 	x86_64_modrm(c.s, OP_STORE, R_RAX, R_RSP, 0, 0, 152);
    434 
    435 	v = find(c, "global", "_save", 0);
    436 	if (!v || !v.member_defined) {
    437 		cdie(c, "no _save");
    438 	}
    439 
    440 	// Save the saved stack and switch back
    441 	as_emit(c.s, OP_GS);
    442 	x86_64_modra(c.s, OP_LOAD, R_RAX, v.member_offset);
    443 	x86_64_modrm(c.s, OP_STORE, R_RAX, R_RSP, 0, 0, 32);
    444 	x86_64_modrr(c.s, OP_MOVE, R_RAX, R_RSP);
    445 
    446 	// Create a frame
    447 	x86_64_modrr(c.s, OP_XORRM, R_RBP, R_RBP);
    448 	x86_64_opr(c.s, OP_PUSHR, R_RBP);
    449 	x86_64_opr(c.s, OP_PUSHR, R_RBP);
    450 	x86_64_modrr(c.s, OP_MOVE, R_RBP, R_RSP);
    451 
    452 	x86_64_modrr(c.s, OP_MOVE, R_RDI, R_RAX);
    453 
    454 	// Call _ssr
    455 	d = find(c, "_ssr", nil, 1);
    456 	if (d.func_defined && d.func_label.fixed) {
    457 		x86_64_jmp(c.s, OP_CALL, d.func_label);
    458 	}
    459 
    460 	x86_64_op(c.s, OP_CLI);
    461 
    462 	// Delete the frame
    463 	x86_64_modri(c.s, OP_ADDI, R_RSP, 2 * 8);
    464 
    465 	// Restore the old registers
    466 	x86_64_modrm(c.s, OP_LOAD, R_RAX, R_RSP, 0, 0, 0);
    467 	x86_64_modrm(c.s, OP_LOAD, R_RDX, R_RSP, 0, 0, 16);
    468 	x86_64_modrm(c.s, OP_LOAD, R_RBX, R_RSP, 0, 0, 24);
    469 	x86_64_modrm(c.s, OP_LOAD, R_RBP, R_RSP, 0, 0, 40);
    470 	x86_64_modrm(c.s, OP_LOAD, R_RSI, R_RSP, 0, 0, 48);
    471 	x86_64_modrm(c.s, OP_LOAD, R_RDI, R_RSP, 0, 0, 56);
    472 	x86_64_modrm(c.s, OP_LOAD, R_R8, R_RSP, 0, 0, 64);
    473 	x86_64_modrm(c.s, OP_LOAD, R_R9, R_RSP, 0, 0, 72);
    474 	x86_64_modrm(c.s, OP_LOAD, R_R10, R_RSP, 0, 0, 80);
    475 	x86_64_modrm(c.s, OP_LOAD, R_R12, R_RSP, 0, 0, 96);
    476 	x86_64_modrm(c.s, OP_LOAD, R_R13, R_RSP, 0, 0, 104);
    477 	x86_64_modrm(c.s, OP_LOAD, R_R14, R_RSP, 0, 0, 112);
    478 	x86_64_modrm(c.s, OP_LOAD, R_R15, R_RSP, 0, 0, 120);
    479 
    480 	x86_64_modrm(c.s, OP_LOAD, R_RCX, R_RSP, 0, 0, 128);
    481 	x86_64_modrm(c.s, OP_LOAD, R_R11, R_RSP, 0, 0, 136);
    482 
    483 	x86_64_modrm(c.s, OP_LOAD, R_RSP, R_RSP, 0, 0, 32);
    484 
    485 	// Return to the user
    486 	x86_64_rex(c.s, OP_SYSRET, 0, 0, 0);
    487 	x86_64_op(c.s, OP_SYSRET);
    488 }
    489 
    490 func x86_64_isr(c: *compiler) {
    491 	var d: *decl;
    492 	var out: *label;
    493 	var i: int;
    494 
    495 	out = mklabel(c.s);
    496 
    497 	i = 0;
    498 	loop {
    499 		if i == 256 {
    500 			break;
    501 		}
    502 		reserve(c.s, 16);
    503 
    504 		if i == 8 || i == 10 || i == 11 || i == 12
    505 				|| i == 13 || i == 14 || i == 17 || i == 21
    506 				|| i == 29 || i == 30 {
    507 			// nop
    508 			as_emit(c.s, 0x90);
    509 			as_emit(c.s, 0x90);
    510 		} else {
    511 			// push 0
    512 			as_emit(c.s, 0x6a);
    513 			as_emit(c.s, 0x00);
    514 		}
    515 
    516 		// push i
    517 		as_emit(c.s, 0x68);
    518 		as_emit(c.s, i);
    519 		as_emit(c.s, 0x00);
    520 		as_emit(c.s, 0x00);
    521 		as_emit(c.s, 0x00);
    522 
    523 		// jmp out
    524 		as_emit(c.s, 0xe9);
    525 		as_emit(c.s, 0x00);
    526 		as_emit(c.s, 0x00);
    527 		as_emit(c.s, 0x00);
    528 		as_emit(c.s, 0x00);
    529 		addfixup(c.s, out, FIXUP_DISP32);
    530 
    531 		// Align to 16
    532 		as_emit(c.s, 0x90);
    533 		as_emit(c.s, 0x90);
    534 		as_emit(c.s, 0x90);
    535 		as_emit(c.s, 0x90);
    536 
    537 		i = i + 1;
    538 	}
    539 
    540 	fixup_label(c.s, out);
    541 
    542 	// Allocate a regs struct
    543 	x86_64_modri(c.s, OP_SUBI, R_RSP, 176);
    544 
    545 	// Save rbp and use it as the regs pointer
    546 	x86_64_modrm(c.s, OP_STORE, R_RBP, R_RSP, 0, 0, 40);
    547 	x86_64_modrr(c.s, OP_MOVE, R_RBP, R_RSP);
    548 
    549 	// Save general purpose registers
    550 	x86_64_modrm(c.s, OP_STORE, R_RAX, R_RBP, 0, 0, 0);
    551 	x86_64_modrm(c.s, OP_STORE, R_RCX, R_RBP, 0, 0, 8);
    552 	x86_64_modrm(c.s, OP_STORE, R_RDX, R_RBP, 0, 0, 16);
    553 	x86_64_modrm(c.s, OP_STORE, R_RBX, R_RBP, 0, 0, 24);
    554 	x86_64_modrm(c.s, OP_STORE, R_RSI, R_RBP, 0, 0, 48);
    555 	x86_64_modrm(c.s, OP_STORE, R_RDI, R_RBP, 0, 0, 56);
    556 	x86_64_modrm(c.s, OP_STORE, R_R8, R_RBP, 0, 0, 64);
    557 	x86_64_modrm(c.s, OP_STORE, R_R9, R_RBP, 0, 0, 72);
    558 	x86_64_modrm(c.s, OP_STORE, R_R10, R_RBP, 0, 0, 80);
    559 	x86_64_modrm(c.s, OP_STORE, R_R11, R_RBP, 0, 0, 88);
    560 	x86_64_modrm(c.s, OP_STORE, R_R12, R_RBP, 0, 0, 96);
    561 	x86_64_modrm(c.s, OP_STORE, R_R13, R_RBP, 0, 0, 104);
    562 	x86_64_modrm(c.s, OP_STORE, R_R14, R_RBP, 0, 0, 112);
    563 	x86_64_modrm(c.s, OP_STORE, R_R15, R_RBP, 0, 0, 120);
    564 
    565 	// trap
    566 	x86_64_modrm(c.s, OP_LOAD, R_RAX, R_RBP, 0, 0, 176 + 0);
    567 	x86_64_modrm(c.s, OP_STORE, R_RAX, R_RBP, 0, 0, 160);
    568 	// err
    569 	x86_64_modrm(c.s, OP_LOAD, R_RAX, R_RBP, 0, 0, 176 + 8);
    570 	x86_64_modrm(c.s, OP_STORE, R_RAX, R_RBP, 0, 0, 168);
    571 	// rip
    572 	x86_64_modrm(c.s, OP_LOAD, R_RAX, R_RBP, 0, 0, 176 + 16);
    573 	x86_64_modrm(c.s, OP_STORE, R_RAX, R_RBP, 0, 0, 128);
    574 	// cs
    575 	x86_64_modrm(c.s, OP_LOAD, R_RAX, R_RBP, 0, 0, 176 + 24);
    576 	x86_64_modrm(c.s, OP_STORE, R_RAX, R_RBP, 0, 0, 144);
    577 	// flags
    578 	x86_64_modrm(c.s, OP_LOAD, R_RAX, R_RBP, 0, 0, 176 + 32);
    579 	x86_64_modrm(c.s, OP_STORE, R_RAX, R_RBP, 0, 0, 136);
    580 	// rsp
    581 	x86_64_modrm(c.s, OP_LOAD, R_RAX, R_RBP, 0, 0, 176 + 40);
    582 	x86_64_modrm(c.s, OP_STORE, R_RAX, R_RBP, 0, 0, 32);
    583 	// ss
    584 	x86_64_modrm(c.s, OP_LOAD, R_RAX, R_RBP, 0, 0, 176 + 48);
    585 	x86_64_modrm(c.s, OP_STORE, R_RAX, R_RBP, 0, 0, 152);
    586 
    587 	// Call _isr
    588 	x86_64_modrr(c.s, OP_MOVE, R_RDI, R_RBP);
    589 	d = find(c, "_isr", nil, 1);
    590 	if (d.func_defined && d.func_label.fixed) {
    591 		x86_64_jmp(c.s, OP_CALL, d.func_label);
    592 	}
    593 
    594 	// rip
    595 	x86_64_modrm(c.s, OP_LOAD, R_RAX, R_RBP, 0, 0, 128);
    596 	x86_64_modrm(c.s, OP_STORE, R_RAX, R_RBP, 0, 0, 176 + 16);
    597 	// cs
    598 	x86_64_modrm(c.s, OP_LOAD, R_RAX, R_RBP, 0, 0, 144);
    599 	x86_64_modrm(c.s, OP_STORE, R_RAX, R_RBP, 0, 0, 176 + 24);
    600 	// flags
    601 	x86_64_modrm(c.s, OP_LOAD, R_RAX, R_RBP, 0, 0, 136);
    602 	x86_64_modrm(c.s, OP_STORE, R_RAX, R_RBP, 0, 0, 176 + 32);
    603 	// rsp
    604 	x86_64_modrm(c.s, OP_LOAD, R_RAX, R_RBP, 0, 0, 32);
    605 	x86_64_modrm(c.s, OP_STORE, R_RAX, R_RBP, 0, 0, 176 + 40);
    606 	// ss
    607 	x86_64_modrm(c.s, OP_LOAD, R_RAX, R_RBP, 0, 0, 152);
    608 	x86_64_modrm(c.s, OP_STORE, R_RAX, R_RBP, 0, 0, 176 + 48);
    609 
    610 	// Restore general purpose registers
    611 	x86_64_modrm(c.s, OP_LOAD, R_RAX, R_RBP, 0, 0, 0);
    612 	x86_64_modrm(c.s, OP_LOAD, R_RCX, R_RBP, 0, 0, 8);
    613 	x86_64_modrm(c.s, OP_LOAD, R_RDX, R_RBP, 0, 0, 16);
    614 	x86_64_modrm(c.s, OP_LOAD, R_RBX, R_RBP, 0, 0, 24);
    615 	x86_64_modrm(c.s, OP_LOAD, R_RSI, R_RBP, 0, 0, 48);
    616 	x86_64_modrm(c.s, OP_LOAD, R_RDI, R_RBP, 0, 0, 56);
    617 	x86_64_modrm(c.s, OP_LOAD, R_R8, R_RBP, 0, 0, 64);
    618 	x86_64_modrm(c.s, OP_LOAD, R_R9, R_RBP, 0, 0, 72);
    619 	x86_64_modrm(c.s, OP_LOAD, R_R10, R_RBP, 0, 0, 80);
    620 	x86_64_modrm(c.s, OP_LOAD, R_R11, R_RBP, 0, 0, 88);
    621 	x86_64_modrm(c.s, OP_LOAD, R_R12, R_RBP, 0, 0, 96);
    622 	x86_64_modrm(c.s, OP_LOAD, R_R13, R_RBP, 0, 0, 104);
    623 	x86_64_modrm(c.s, OP_LOAD, R_R14, R_RBP, 0, 0, 112);
    624 	x86_64_modrm(c.s, OP_LOAD, R_R15, R_RBP, 0, 0, 120);
    625 
    626 	// Restore rbp
    627 	x86_64_modrm(c.s, OP_LOAD, R_RBP, R_RBP, 0, 0, 40);
    628 
    629 	// Clean up regs + trap + err
    630 	x86_64_modri(c.s, OP_ADDI, R_RSP, 176 + 2 * 8);
    631 
    632 	x86_64_op(c.s, OP_IRETQ);
    633 }
    634 
    635 func x86_64_builtin(c: *compiler) {
    636 	var d: *decl;
    637 
    638 	d = find(c, "syscall", nil, 1);
    639 	if (d.func_defined && !d.func_label.fixed) {
    640 		fixup_label(c.s, d.func_label);
    641 		add_symbol(c.s, d.name, d.func_label);
    642 		x86_64_modrr(c.s, OP_MOVE, R_RAX, R_RDI);
    643 		x86_64_modrr(c.s, OP_MOVE, R_RDI, R_RSI);
    644 		x86_64_modrr(c.s, OP_MOVE, R_RSI, R_RDX);
    645 		x86_64_modrr(c.s, OP_MOVE, R_RDX, R_RCX);
    646 		x86_64_modrr(c.s, OP_MOVE, R_R10, R_R8);
    647 		x86_64_modrr(c.s, OP_MOVE, R_R8, R_R9);
    648 		x86_64_modrm(c.s, OP_LOAD, R_R9, R_RSP, 0, 0, 8);
    649 		x86_64_op(c.s, OP_SYSCALL);
    650 		x86_64_op(c.s, OP_RET);
    651 	}
    652 
    653 	d = find(c, "_restorer", nil, 1);
    654 	if (d.func_defined && !d.func_label.fixed) {
    655 		fixup_label(c.s, d.func_label);
    656 		add_symbol(c.s, d.name, d.func_label);
    657 		x86_64_modri(c.s, OP_MOVI, R_RAX, 15);
    658 		x86_64_op(c.s, OP_SYSCALL);
    659 	}
    660 
    661 	d = find(c, "_include", nil, 1);
    662 	if (d.func_defined && !d.func_label.fixed) {
    663 		fixup_label(c.s, d.func_label);
    664 		add_symbol(c.s, d.name, d.func_label);
    665 		x86_64_op(c.s, OP_UD2);
    666 	}
    667 
    668 	d = find(c, "ud2", nil, 1);
    669 	if (d.func_defined && !d.func_label.fixed) {
    670 		fixup_label(c.s, d.func_label);
    671 		add_symbol(c.s, d.name, d.func_label);
    672 		x86_64_op(c.s, OP_UD2);
    673 	}
    674 
    675 	d = find(c, "cpuid", nil, 1);
    676 	if (d.func_defined && !d.func_label.fixed) {
    677 		fixup_label(c.s, d.func_label);
    678 		add_symbol(c.s, d.name, d.func_label);
    679 		x86_64_opr(c.s, OP_PUSHR, R_RCX);
    680 		x86_64_opr(c.s, OP_PUSHR, R_RDX);
    681 		x86_64_opr(c.s, OP_PUSHR, R_RSI);
    682 		x86_64_opr(c.s, OP_PUSHR, R_RDI);
    683 		x86_64_modrm(c.s, OP_LOAD, R_RAX, R_RDI, 0, 0, 0);
    684 		x86_64_modrm(c.s, OP_LOAD, R_RCX, R_RSI, 0, 0, 0);
    685 		x86_64_modrm(c.s, OP_LOAD, R_RDX, R_RDX, 0, 0, 0);
    686 		x86_64_modrm(c.s, OP_LOAD, R_RBX, R_RCX, 0, 0, 0);
    687 		x86_64_op(c.s, OP_CPUID);
    688 		x86_64_opr(c.s, OP_POPR, R_RDI);
    689 		x86_64_opr(c.s, OP_POPR, R_RSI);
    690 		x86_64_opr(c.s, OP_POPR, R_RDX);
    691 		x86_64_opr(c.s, OP_POPR, R_RCX);
    692 		x86_64_modrm(c.s, OP_STORE, R_RAX, R_RDI, 0, 0, 0);
    693 		x86_64_modrm(c.s, OP_STORE, R_RCX, R_RSI, 0, 0, 0);
    694 		x86_64_modrm(c.s, OP_STORE, R_RDX, R_RDX, 0, 0, 0);
    695 		x86_64_modrm(c.s, OP_STORE, R_RBX, R_RCX, 0, 0, 0);
    696 		x86_64_op(c.s, OP_RET);
    697 	}
    698 
    699 	d = find(c, "inb", nil, 1);
    700 	if (d.func_defined && !d.func_label.fixed) {
    701 		fixup_label(c.s, d.func_label);
    702 		add_symbol(c.s, d.name, d.func_label);
    703 		x86_64_modrr(c.s, OP_MOVE, R_RDX, R_RDI);
    704 		x86_64_op(c.s, OP_IN);
    705 		x86_64_op(c.s, OP_RET);
    706 	}
    707 
    708 	d = find(c, "outb", nil, 1);
    709 	if (d.func_defined && !d.func_label.fixed) {
    710 		fixup_label(c.s, d.func_label);
    711 		add_symbol(c.s, d.name, d.func_label);
    712 		x86_64_modrr(c.s, OP_MOVE, R_RDX, R_RDI);
    713 		x86_64_modrr(c.s, OP_MOVE, R_RAX, R_RSI);
    714 		x86_64_op(c.s, OP_OUT);
    715 		x86_64_op(c.s, OP_RET);
    716 	}
    717 
    718 	d = find(c, "inw", nil, 1);
    719 	if (d.func_defined && !d.func_label.fixed) {
    720 		fixup_label(c.s, d.func_label);
    721 		add_symbol(c.s, d.name, d.func_label);
    722 		x86_64_modrr(c.s, OP_MOVE, R_RDX, R_RDI);
    723 		as_emit(c.s, OP_OS);
    724 		x86_64_op(c.s, OP_IND);
    725 		x86_64_op(c.s, OP_RET);
    726 	}
    727 
    728 	d = find(c, "outw", nil, 1);
    729 	if (d.func_defined && !d.func_label.fixed) {
    730 		fixup_label(c.s, d.func_label);
    731 		add_symbol(c.s, d.name, d.func_label);
    732 		x86_64_modrr(c.s, OP_MOVE, R_RDX, R_RDI);
    733 		x86_64_modrr(c.s, OP_MOVE, R_RAX, R_RSI);
    734 		as_emit(c.s, OP_OS);
    735 		x86_64_op(c.s, OP_OUTD);
    736 		x86_64_op(c.s, OP_RET);
    737 	}
    738 
    739 	d = find(c, "ind", nil, 1);
    740 	if (d.func_defined && !d.func_label.fixed) {
    741 		fixup_label(c.s, d.func_label);
    742 		add_symbol(c.s, d.name, d.func_label);
    743 		x86_64_modrr(c.s, OP_MOVE, R_RDX, R_RDI);
    744 		x86_64_op(c.s, OP_IND);
    745 		x86_64_op(c.s, OP_RET);
    746 	}
    747 
    748 	d = find(c, "outd", nil, 1);
    749 	if (d.func_defined && !d.func_label.fixed) {
    750 		fixup_label(c.s, d.func_label);
    751 		add_symbol(c.s, d.name, d.func_label);
    752 		x86_64_modrr(c.s, OP_MOVE, R_RDX, R_RDI);
    753 		x86_64_modrr(c.s, OP_MOVE, R_RAX, R_RSI);
    754 		x86_64_op(c.s, OP_OUTD);
    755 		x86_64_op(c.s, OP_RET);
    756 	}
    757 
    758 	d = find(c, "rdmsr", nil, 1);
    759 	if (d.func_defined && !d.func_label.fixed) {
    760 		fixup_label(c.s, d.func_label);
    761 		add_symbol(c.s, d.name, d.func_label);
    762 		x86_64_modrr(c.s, OP_MOVE, R_RCX, R_RDI);
    763 		x86_64_op(c.s, OP_RDMSR);
    764 		x86_64_modri(c.s, OP_MOVI, R_RCX, 32);
    765 		x86_64_modr(c.s, OP_SHLM, R_RDX);
    766 		x86_64_modrr(c.s, OP_ORRM, R_RAX, R_RDX);
    767 		x86_64_op(c.s, OP_RET);
    768 	}
    769 
    770 	d = find(c, "wrmsr", nil, 1);
    771 	if (d.func_defined && !d.func_label.fixed) {
    772 		fixup_label(c.s, d.func_label);
    773 		add_symbol(c.s, d.name, d.func_label);
    774 		x86_64_modrr(c.s, OP_MOVE, R_RAX, R_RSI);
    775 		x86_64_modrr(c.s, OP_MOVE, R_RDX, R_RSI);
    776 		x86_64_modri(c.s, OP_MOVI, R_RCX, 32);
    777 		x86_64_modr(c.s, OP_SHRM, R_RDX);
    778 		x86_64_modrr(c.s, OP_MOVE, R_RCX, R_RDI);
    779 		x86_64_op(c.s, OP_WRMSR);
    780 		x86_64_op(c.s, OP_RET);
    781 	}
    782 
    783 	d = find(c, "rdcr0", nil, 1);
    784 	if (d.func_defined && !d.func_label.fixed) {
    785 		fixup_label(c.s, d.func_label);
    786 		add_symbol(c.s, d.name, d.func_label);
    787 		x86_64_modrr(c.s, OP_RDCRR, R_CR0, R_RAX);
    788 		x86_64_op(c.s, OP_RET);
    789 	}
    790 
    791 	d = find(c, "wrcr0", nil, 1);
    792 	if (d.func_defined && !d.func_label.fixed) {
    793 		fixup_label(c.s, d.func_label);
    794 		add_symbol(c.s, d.name, d.func_label);
    795 		x86_64_modrr(c.s, OP_WRCRR, R_CR0, R_RDI);
    796 		x86_64_op(c.s, OP_RET);
    797 	}
    798 
    799 	d = find(c, "rdcr2", nil, 1);
    800 	if (d.func_defined && !d.func_label.fixed) {
    801 		fixup_label(c.s, d.func_label);
    802 		add_symbol(c.s, d.name, d.func_label);
    803 		x86_64_modrr(c.s, OP_RDCRR, R_CR2, R_RAX);
    804 		x86_64_op(c.s, OP_RET);
    805 	}
    806 
    807 	d = find(c, "wrcr2", nil, 1);
    808 	if (d.func_defined && !d.func_label.fixed) {
    809 		fixup_label(c.s, d.func_label);
    810 		add_symbol(c.s, d.name, d.func_label);
    811 		x86_64_modrr(c.s, OP_WRCRR, R_CR2, R_RDI);
    812 		x86_64_op(c.s, OP_RET);
    813 	}
    814 
    815 	d = find(c, "rdcr3", nil, 1);
    816 	if (d.func_defined && !d.func_label.fixed) {
    817 		fixup_label(c.s, d.func_label);
    818 		add_symbol(c.s, d.name, d.func_label);
    819 		x86_64_modrr(c.s, OP_RDCRR, R_CR3, R_RAX);
    820 		x86_64_op(c.s, OP_RET);
    821 	}
    822 
    823 	d = find(c, "wrcr3", nil, 1);
    824 	if (d.func_defined && !d.func_label.fixed) {
    825 		fixup_label(c.s, d.func_label);
    826 		add_symbol(c.s, d.name, d.func_label);
    827 		x86_64_modrr(c.s, OP_WRCRR, R_CR3, R_RDI);
    828 		x86_64_op(c.s, OP_RET);
    829 	}
    830 
    831 	d = find(c, "rdcr4", nil, 1);
    832 	if (d.func_defined && !d.func_label.fixed) {
    833 		fixup_label(c.s, d.func_label);
    834 		add_symbol(c.s, d.name, d.func_label);
    835 		x86_64_modrr(c.s, OP_RDCRR, R_CR4, R_RAX);
    836 		x86_64_op(c.s, OP_RET);
    837 	}
    838 
    839 	d = find(c, "wrcr4", nil, 1);
    840 	if (d.func_defined && !d.func_label.fixed) {
    841 		fixup_label(c.s, d.func_label);
    842 		add_symbol(c.s, d.name, d.func_label);
    843 		x86_64_modrr(c.s, OP_WRCRR, R_CR4, R_RDI);
    844 		x86_64_op(c.s, OP_RET);
    845 	}
    846 
    847 	d = find(c, "lgdt", nil, 1);
    848 	if (d.func_defined && !d.func_label.fixed) {
    849 		fixup_label(c.s, d.func_label);
    850 		add_symbol(c.s, d.name, d.func_label);
    851 		x86_64_modri(c.s, OP_SUBI, R_RSP, 16);
    852 		x86_64_modri(c.s, OP_SUBI, R_RSI, 1);
    853 		x86_64_modrm(c.s, OP_STORE, R_RSI, R_RSP, 0, 0, 0);
    854 		x86_64_modrm(c.s, OP_STORE, R_RDI, R_RSP, 0, 0, 2);
    855 		x86_64_modm(c.s, OP_LGDTM, R_RSP, 0, 0, 0);
    856 		x86_64_modri(c.s, OP_ADDI, R_RSP, 16);
    857 		x86_64_op(c.s, OP_RET);
    858 	}
    859 
    860 	d = find(c, "lidt", nil, 1);
    861 	if (d.func_defined && !d.func_label.fixed) {
    862 		fixup_label(c.s, d.func_label);
    863 		add_symbol(c.s, d.name, d.func_label);
    864 		x86_64_modri(c.s, OP_SUBI, R_RSP, 16);
    865 		x86_64_modri(c.s, OP_SUBI, R_RSI, 1);
    866 		x86_64_modrm(c.s, OP_STORE, R_RSI, R_RSP, 0, 0, 0);
    867 		x86_64_modrm(c.s, OP_STORE, R_RDI, R_RSP, 0, 0, 2);
    868 		x86_64_modm(c.s, OP_LIDTM, R_RSP, 0, 0, 0);
    869 		x86_64_modri(c.s, OP_ADDI, R_RSP, 16);
    870 		x86_64_op(c.s, OP_RET);
    871 	}
    872 
    873 	d = find(c, "lldt", nil, 1);
    874 	if (d.func_defined && !d.func_label.fixed) {
    875 		fixup_label(c.s, d.func_label);
    876 		add_symbol(c.s, d.name, d.func_label);
    877 		x86_64_modr(c.s, OP_LLDTM, R_RDI);
    878 		x86_64_op(c.s, OP_RET);
    879 	}
    880 
    881 	d = find(c, "ltr", nil, 1);
    882 	if (d.func_defined && !d.func_label.fixed) {
    883 		fixup_label(c.s, d.func_label);
    884 		add_symbol(c.s, d.name, d.func_label);
    885 		x86_64_modr(c.s, OP_LTRM, R_RDI);
    886 		x86_64_op(c.s, OP_RET);
    887 	}
    888 
    889 	d = find(c, "lseg", nil, 1);
    890 	if (d.func_defined && !d.func_label.fixed) {
    891 		fixup_label(c.s, d.func_label);
    892 		add_symbol(c.s, d.name, d.func_label);
    893 		x86_64_opr(c.s, OP_PUSHR, R_RBP);
    894 		x86_64_modrr(c.s, OP_MOVE, R_RBP, R_RSP);
    895 		// es ds fs gs
    896 		x86_64_modrr(c.s, OP_WRSR, R_ES, R_RSI);
    897 		x86_64_modrr(c.s, OP_WRSR, R_DS, R_RSI);
    898 		x86_64_modrr(c.s, OP_WRSR, R_FS, R_RSI);
    899 		x86_64_modrr(c.s, OP_WRSR, R_GS, R_RSI);
    900 		// ss
    901 		x86_64_opr(c.s, OP_PUSHR, R_RSI);
    902 		// rsp
    903 		x86_64_opr(c.s, OP_PUSHR, R_RBP);
    904 		// flags
    905 		x86_64_op(c.s, OP_PUSHF);
    906 		// cs
    907 		x86_64_opr(c.s, OP_PUSHR, R_RDI);
    908 		// rip
    909 		x86_64_op(c.s, OP_CALL);
    910 		as_emit(c.s, 5);
    911 		as_emit(c.s, 0);
    912 		as_emit(c.s, 0);
    913 		as_emit(c.s, 0);
    914 		x86_64_op(c.s, OP_JMP);
    915 		as_emit(c.s, 2);
    916 		as_emit(c.s, 0);
    917 		as_emit(c.s, 0);
    918 		as_emit(c.s, 0);
    919 		x86_64_op(c.s, OP_IRETQ);
    920 		x86_64_opr(c.s, OP_POPR, R_RBP);
    921 		x86_64_op(c.s, OP_RET);
    922 	}
    923 
    924 	d = find(c, "hlt", nil, 1);
    925 	if (d.func_defined && !d.func_label.fixed) {
    926 		fixup_label(c.s, d.func_label);
    927 		add_symbol(c.s, d.name, d.func_label);
    928 		x86_64_op(c.s, OP_HLT);
    929 		x86_64_op(c.s, OP_RET);
    930 	}
    931 
    932 	d = find(c, "cli", nil, 1);
    933 	if (d.func_defined && !d.func_label.fixed) {
    934 		fixup_label(c.s, d.func_label);
    935 		add_symbol(c.s, d.name, d.func_label);
    936 		x86_64_op(c.s, OP_CLI);
    937 		x86_64_op(c.s, OP_RET);
    938 	}
    939 
    940 	d = find(c, "sti", nil, 1);
    941 	if (d.func_defined && !d.func_label.fixed) {
    942 		fixup_label(c.s, d.func_label);
    943 		add_symbol(c.s, d.name, d.func_label);
    944 		x86_64_op(c.s, OP_STI);
    945 		x86_64_op(c.s, OP_RET);
    946 	}
    947 
    948 	d = find(c, "rdflags", nil, 1);
    949 	if (d.func_defined && !d.func_label.fixed) {
    950 		fixup_label(c.s, d.func_label);
    951 		add_symbol(c.s, d.name, d.func_label);
    952 		x86_64_op(c.s, OP_PUSHF);
    953 		x86_64_opr(c.s, OP_POPR, R_RAX);
    954 		x86_64_op(c.s, OP_RET);
    955 	}
    956 
    957 	d = find(c, "wrflags", nil, 1);
    958 	if (d.func_defined && !d.func_label.fixed) {
    959 		fixup_label(c.s, d.func_label);
    960 		add_symbol(c.s, d.name, d.func_label);
    961 		x86_64_opr(c.s, OP_PUSHR, R_RDI);
    962 		x86_64_op(c.s, OP_POPF);
    963 		x86_64_op(c.s, OP_RET);
    964 	}
    965 
    966 	d = find(c, "wbinvld", nil, 1);
    967 	if (d.func_defined && !d.func_label.fixed) {
    968 		fixup_label(c.s, d.func_label);
    969 		add_symbol(c.s, d.name, d.func_label);
    970 		x86_64_modm(c.s, OP_WBINVD, R_RDI, 0, 0, 0);
    971 		x86_64_op(c.s, OP_RET);
    972 	}
    973 
    974 	d = find(c, "invlpg", nil, 1);
    975 	if (d.func_defined && !d.func_label.fixed) {
    976 		fixup_label(c.s, d.func_label);
    977 		add_symbol(c.s, d.name, d.func_label);
    978 		x86_64_modm(c.s, OP_INVLPGM, R_RDI, 0, 0, 0);
    979 		x86_64_op(c.s, OP_RET);
    980 	}
    981 
    982 	d = find(c, "_ssr0", nil, 1);
    983 	if (d.func_defined && !d.func_label.fixed) {
    984 		fixup_label(c.s, d.func_label);
    985 		add_symbol(c.s, d.name, d.func_label);
    986 		x86_64_ssr(c);
    987 		x86_64_op(c.s, OP_RET);
    988 	}
    989 
    990 	d = find(c, "_isr0", nil, 1);
    991 	if (d.func_defined && !d.func_label.fixed) {
    992 		fixup_label(c.s, d.func_label);
    993 		add_symbol(c.s, d.name, d.func_label);
    994 		x86_64_isr(c);
    995 		x86_64_op(c.s, OP_RET);
    996 	}
    997 
    998 	d = find(c, "_rgs", nil, 1);
    999 	if (d.func_defined && !d.func_label.fixed) {
   1000 		fixup_label(c.s, d.func_label);
   1001 		add_symbol(c.s, d.name, d.func_label);
   1002 		x86_64_modrm(c.s, OP_LOAD, R_RSI, R_RBP, 0, 0, 16);
   1003 		as_emit(c.s, OP_GS);
   1004 		x86_64_modrm(c.s, OP_LOAD, R_RAX, R_RSI, 0, 0, 0);
   1005 		x86_64_op(c.s, OP_RET);
   1006 	}
   1007 
   1008 	d = find(c, "_r32", nil, 1);
   1009 	if (d.func_defined && !d.func_label.fixed) {
   1010 		fixup_label(c.s, d.func_label);
   1011 		add_symbol(c.s, d.name, d.func_label);
   1012 		c.s.bits32 = 1;
   1013 		x86_64_modrm(c.s, OP_LOAD, R_RAX, R_RDI, 0, 0, 0);
   1014 		c.s.bits32 = 0;
   1015 		x86_64_op(c.s, OP_RET);
   1016 	}
   1017 
   1018 	d = find(c, "_w32", nil, 1);
   1019 	if (d.func_defined && !d.func_label.fixed) {
   1020 		fixup_label(c.s, d.func_label);
   1021 		add_symbol(c.s, d.name, d.func_label);
   1022 		c.s.bits32 = 1;
   1023 		x86_64_modrm(c.s, OP_STORE, R_RSI, R_RDI, 0, 0, 0);
   1024 		c.s.bits32 = 0;
   1025 		x86_64_op(c.s, OP_RET);
   1026 	}
   1027 
   1028 	d = find(c, "_r16", nil, 1);
   1029 	if (d.func_defined && !d.func_label.fixed) {
   1030 		fixup_label(c.s, d.func_label);
   1031 		add_symbol(c.s, d.name, d.func_label);
   1032 		x86_64_modrr(c.s, OP_XORRM, R_RAX, R_RAX);
   1033 		c.s.bits32 = 1;
   1034 		x86_64_modrm(c.s, OP_LOAD16, R_RAX, R_RDI, 0, 0, 0);
   1035 		c.s.bits32 = 0;
   1036 		x86_64_op(c.s, OP_RET);
   1037 	}
   1038 
   1039 	d = find(c, "_w16", nil, 1);
   1040 	if (d.func_defined && !d.func_label.fixed) {
   1041 		fixup_label(c.s, d.func_label);
   1042 		add_symbol(c.s, d.name, d.func_label);
   1043 		c.s.bits32 = 1;
   1044 		x86_64_modrm(c.s, OP_STORE16, R_RSI, R_RDI, 0, 0, 0);
   1045 		c.s.bits32 = 0;
   1046 		x86_64_op(c.s, OP_RET);
   1047 	}
   1048 
   1049 	d = find(c, "_rdrand", nil, 1);
   1050 	if (d.func_defined && !d.func_label.fixed) {
   1051 		fixup_label(c.s, d.func_label);
   1052 		add_symbol(c.s, d.name, d.func_label);
   1053 		x86_64_modr(c.s, OP_RDRAND, R_RAX);
   1054 		x86_64_op(c.s, OP_RET);
   1055 	}
   1056 
   1057 	d = find(c, "taskswitch", nil, 1);
   1058 	if (d.func_defined && !d.func_label.fixed) {
   1059 		fixup_label(c.s, d.func_label);
   1060 		add_symbol(c.s, d.name, d.func_label);
   1061 
   1062 		// save
   1063 		x86_64_modrm(c.s, OP_STORE, R_RAX, R_RDI, 0, 0, 0);
   1064 		x86_64_modrm(c.s, OP_STORE, R_RCX, R_RDI, 0, 0, 8);
   1065 		x86_64_modrm(c.s, OP_STORE, R_RDX, R_RDI, 0, 0, 16);
   1066 		x86_64_modrm(c.s, OP_STORE, R_RBX, R_RDI, 0, 0, 24);
   1067 		x86_64_modrm(c.s, OP_STORE, R_RBP, R_RDI, 0, 0, 40);
   1068 		x86_64_modrm(c.s, OP_STORE, R_RSI, R_RDI, 0, 0, 48);
   1069 		x86_64_modrm(c.s, OP_STORE, R_RDI, R_RDI, 0, 0, 56);
   1070 		x86_64_modrm(c.s, OP_STORE, R_R8, R_RDI, 0, 0, 64);
   1071 		x86_64_modrm(c.s, OP_STORE, R_R9, R_RDI, 0, 0, 72);
   1072 		x86_64_modrm(c.s, OP_STORE, R_R10, R_RDI, 0, 0, 80);
   1073 		x86_64_modrm(c.s, OP_STORE, R_R11, R_RDI, 0, 0, 88);
   1074 		x86_64_modrm(c.s, OP_STORE, R_R12, R_RDI, 0, 0, 96);
   1075 		x86_64_modrm(c.s, OP_STORE, R_R13, R_RDI, 0, 0, 104);
   1076 		x86_64_modrm(c.s, OP_STORE, R_R14, R_RDI, 0, 0, 112);
   1077 		x86_64_modrm(c.s, OP_STORE, R_R15, R_RDI, 0, 0, 120);
   1078 
   1079 		// rip
   1080 		x86_64_opr(c.s, OP_POPR, R_RAX);
   1081 		x86_64_modrm(c.s, OP_STORE, R_RAX, R_RDI, 0, 0, 128);
   1082 		// cs
   1083 		x86_64_modrr(c.s, OP_RDSR, R_CS, R_RAX);
   1084 		x86_64_modrm(c.s, OP_STORE, R_RAX, R_RDI, 0, 0, 144);
   1085 		// flags
   1086 		x86_64_op(c.s, OP_PUSHF);
   1087 		x86_64_opr(c.s, OP_POPR, R_RAX);
   1088 		x86_64_modrm(c.s, OP_STORE, R_RAX, R_RDI, 0, 0, 136);
   1089 		// rsp
   1090 		x86_64_modrm(c.s, OP_STORE, R_RSP, R_RDI, 0, 0, 32);
   1091 		// ss
   1092 		x86_64_modrr(c.s, OP_RDSR, R_SS, R_RAX);
   1093 		x86_64_modrm(c.s, OP_STORE, R_RAX, R_RDI, 0, 0, 152);
   1094 
   1095 		// restore
   1096 		x86_64_modrm(c.s, OP_STORE, R_RCX, R_RDI, 0, 0, 8);
   1097 		x86_64_modrm(c.s, OP_STORE, R_RDX, R_RDI, 0, 0, 16);
   1098 		x86_64_modrm(c.s, OP_STORE, R_RBX, R_RDI, 0, 0, 24);
   1099 		x86_64_modrm(c.s, OP_STORE, R_RBP, R_RDI, 0, 0, 40);
   1100 		x86_64_modrm(c.s, OP_STORE, R_RDI, R_RDI, 0, 0, 56);
   1101 		x86_64_modrm(c.s, OP_STORE, R_R8, R_RDI, 0, 0, 64);
   1102 		x86_64_modrm(c.s, OP_STORE, R_R9, R_RDI, 0, 0, 72);
   1103 		x86_64_modrm(c.s, OP_STORE, R_R10, R_RDI, 0, 0, 80);
   1104 		x86_64_modrm(c.s, OP_STORE, R_R11, R_RDI, 0, 0, 88);
   1105 		x86_64_modrm(c.s, OP_STORE, R_R12, R_RDI, 0, 0, 96);
   1106 		x86_64_modrm(c.s, OP_STORE, R_R13, R_RDI, 0, 0, 104);
   1107 		x86_64_modrm(c.s, OP_STORE, R_R14, R_RDI, 0, 0, 112);
   1108 		x86_64_modrm(c.s, OP_STORE, R_R15, R_RDI, 0, 0, 120);
   1109 
   1110 		// ss
   1111 		x86_64_modrm(c.s, OP_LOAD, R_RAX, R_RSI, 0, 0, 152);
   1112 		x86_64_opr(c.s, OP_PUSHR, R_RAX);
   1113 		// rsp
   1114 		x86_64_modrm(c.s, OP_LOAD, R_RAX, R_RSI, 0, 0, 32);
   1115 		x86_64_opr(c.s, OP_PUSHR, R_RAX);
   1116 		// flags
   1117 		x86_64_modrm(c.s, OP_LOAD, R_RAX, R_RSI, 0, 0, 136);
   1118 		x86_64_opr(c.s, OP_PUSHR, R_RAX);
   1119 		// cs
   1120 		x86_64_modrm(c.s, OP_LOAD, R_RAX, R_RSI, 0, 0, 144);
   1121 		x86_64_opr(c.s, OP_PUSHR, R_RAX);
   1122 		// rip
   1123 		x86_64_modrm(c.s, OP_LOAD, R_RAX, R_RSI, 0, 0, 128);
   1124 		x86_64_opr(c.s, OP_PUSHR, R_RAX);
   1125 
   1126 		// restore temporaries
   1127 		x86_64_modrm(c.s, OP_LOAD, R_RAX, R_RSI, 0, 0, 0);
   1128 		x86_64_modrm(c.s, OP_LOAD, R_RSI, R_RSI, 0, 0, 40);
   1129 
   1130 		// iretq
   1131 		x86_64_op(c.s, OP_IRETQ);
   1132 	}
   1133 }
   1134 
   1135 func x86_64_kstart(c: *assembler) {
   1136 	var hang: *label;
   1137 	var do_iret: *label;
   1138 	var do_ret: *label;
   1139 	var done: *label;
   1140 
   1141 	c.bits32 = 1;
   1142 
   1143 	hang = mklabel(c);
   1144 	do_iret = mklabel(c);
   1145 	do_ret = mklabel(c);
   1146 	done = mklabel(c);
   1147 
   1148 	// Check for valid multiboot magic
   1149 	x86_64_modri(c, OP_MOVI, R_RDX, 0x2badb002);
   1150 	x86_64_modrr(c, OP_CMPRM, R_RAX, R_RDX);
   1151 	x86_64_jmp(c, OP_JCC + CC_NE, hang);
   1152 
   1153 	// Setup an initial stack
   1154 	x86_64_modri(c, OP_MOVI, R_RSP, 0x00300000); // FIXME bss
   1155 
   1156 	// Align stack to page
   1157 	x86_64_modri(c, OP_ANDI, R_RSP, -0x1000);
   1158 
   1159 	// pt3 -> 1g
   1160 	x86_64_modri(c, OP_SUBI, R_RSP, 0x1000);
   1161 	x86_64_modri(c, OP_MOVI, R_RAX, 0x83);
   1162 	x86_64_modri(c, OP_MOVI, R_RDX, 0);
   1163 	x86_64_modrm(c, OP_STORE, R_RAX, R_RSP, 0, 0, 0);
   1164 	x86_64_modrm(c, OP_STORE, R_RDX, R_RSP, 0, 0, 4);
   1165 	x86_64_modrm(c, OP_STORE, R_RAX, R_RSP, 0, 0, 510 * 8 + 0);
   1166 	x86_64_modrm(c, OP_STORE, R_RDX, R_RSP, 0, 0, 510 * 8 + 4);
   1167 
   1168 	// pt4 -> pt3
   1169 	x86_64_modrr(c, OP_MOVE, R_RAX, R_RSP);
   1170 	x86_64_modri(c, OP_SUBI, R_RSP, 0x1000);
   1171 	x86_64_modri(c, OP_ORI, R_RAX, 3);
   1172 	x86_64_modri(c, OP_MOVI, R_RDX, 0);
   1173 	x86_64_modrm(c, OP_STORE, R_RAX, R_RSP, 0, 0, 0);
   1174 	x86_64_modrm(c, OP_STORE, R_RDX, R_RSP, 0, 0, 4);
   1175 	x86_64_modrm(c, OP_STORE, R_RAX, R_RSP, 0, 0, 511 * 8 + 0);
   1176 	x86_64_modrm(c, OP_STORE, R_RDX, R_RSP, 0, 0, 511 * 8 + 4);
   1177 
   1178 	// Load page table pt4
   1179 	x86_64_modrr(c, OP_WRCRR, R_CR3, R_RSP);
   1180 
   1181 	// Allocate space for the gdt
   1182 	x86_64_modri(c, OP_SUBI, R_RSP, 64);
   1183 	x86_64_modrr(c, OP_MOVE, R_RBP, R_RSP);
   1184 
   1185 	// Null Segment
   1186 	x86_64_modri(c, OP_MOVI, R_RAX, 0x00000000);
   1187 	x86_64_modrm(c, OP_STORE, R_RAX, R_RBP, 0, 0, 8);
   1188 	x86_64_modri(c, OP_MOVI, R_RAX, 0x00000000);
   1189 	x86_64_modrm(c, OP_STORE, R_RAX, R_RBP, 0, 0, 12);
   1190 
   1191 	// Kernel code segment
   1192 	x86_64_modri(c, OP_MOVI, R_RAX, 0x00000000);
   1193 	x86_64_modrm(c, OP_STORE, R_RAX, R_RBP, 0, 0, 16);
   1194 	x86_64_modri(c, OP_MOVI, R_RAX, 0x00209800);
   1195 	x86_64_modrm(c, OP_STORE, R_RAX, R_RBP, 0, 0, 20);
   1196 
   1197 	// Kernel data segment
   1198 	x86_64_modri(c, OP_MOVI, R_RAX, 0x00000000);
   1199 	x86_64_modrm(c, OP_STORE, R_RAX, R_RBP, 0, 0, 24);
   1200 	x86_64_modri(c, OP_MOVI, R_RAX, 0x00009200);
   1201 	x86_64_modrm(c, OP_STORE, R_RAX, R_RBP, 0, 0, 28);
   1202 
   1203 	// Load gdt
   1204 	x86_64_modri(c, OP_MOVI, R_RAX, 23);
   1205 	x86_64_modrm(c, OP_STORE, R_RAX, R_RBP, 0, 0, 0);
   1206 	x86_64_modrm(c, OP_LEA, R_RAX, R_RBP, 0, 0, 8);
   1207 	x86_64_modrm(c, OP_STORE, R_RAX, R_RBP, 0, 0, 2);
   1208 	x86_64_modm(c, OP_LGDTM, R_RBP, 0, 0, 0);
   1209 
   1210 	// Load null lldt
   1211 	x86_64_modri(c, OP_MOVI, R_RAX, 0);
   1212 	x86_64_modr(c, OP_LLDTM, R_RAX);
   1213 
   1214 	// Load null idt
   1215 	x86_64_modm(c, OP_LIDTM, R_RBP, 0, 0, 8);
   1216 
   1217 	// Enable pae
   1218 	x86_64_modri(c, OP_MOVI, R_RAX, 0xa0);
   1219 	x86_64_modrr(c, OP_WRCRR, R_CR4, R_RAX);
   1220 
   1221 	// Enable long mode
   1222 	x86_64_modri(c, OP_MOVI, R_RCX, (-1 << 32) + (0xc0 << 24) + 0x000080);
   1223 	x86_64_op(c, OP_RDMSR);
   1224 	x86_64_modri(c, OP_ORI, R_RAX, 0x100);
   1225 	x86_64_op(c, OP_WRMSR);
   1226 
   1227 	// Enable paging
   1228 	x86_64_modrr(c, OP_RDCRR, R_CR0, R_RAX);
   1229 	x86_64_modri(c, OP_ORI, R_RAX, (-0x80000000) | 0x0001);
   1230 	x86_64_modrr(c, OP_WRCRR, R_CR0, R_RAX);
   1231 
   1232 	// flags
   1233 	x86_64_modri(c, OP_MOVI, R_RAX, 0);
   1234 	x86_64_opr(c, OP_PUSHR, R_RAX);
   1235 	// cs
   1236 	x86_64_modri(c, OP_MOVI, R_RAX, 8);
   1237 	x86_64_opr(c, OP_PUSHR, R_RAX);
   1238 	// pointer
   1239 	x86_64_jmp(c, OP_CALL, do_iret);
   1240 
   1241 	c.bits32 = 0;
   1242 
   1243 	// Jump to top half
   1244 	x86_64_jmp(c, OP_CALL, do_ret);
   1245 
   1246 	// Reload the gdt in the top half
   1247 	x86_64_modri(c, OP_ORI, R_RBP, -0x80000000);
   1248 	x86_64_modri(c, OP_MOVI, R_RAX, 23);
   1249 	x86_64_modrm(c, OP_STORE, R_RAX, R_RBP, 0, 0, 0);
   1250 	x86_64_modrm(c, OP_LEA, R_RAX, R_RBP, 0, 0, 8);
   1251 	x86_64_modrm(c, OP_STORE, R_RAX, R_RBP, 0, 0, 2);
   1252 	x86_64_modm(c, OP_LGDTM, R_RBP, 0, 0, 0);
   1253 
   1254 	// Reload segments
   1255 	x86_64_modri(c, OP_MOVI, R_RAX, 16);
   1256 	x86_64_modrr(c, OP_WRSR, R_ES, R_RAX);
   1257 	x86_64_modrr(c, OP_WRSR, R_DS, R_RAX);
   1258 	x86_64_modrr(c, OP_WRSR, R_FS, R_RAX);
   1259 	x86_64_modrr(c, OP_WRSR, R_GS, R_RAX);
   1260 	x86_64_modrr(c, OP_WRSR, R_SS, R_RAX);
   1261 	x86_64_modrr(c, OP_MOVE, R_RSP, R_RSP);
   1262 
   1263 	// Reload stack in the top half
   1264 	x86_64_modri(c, OP_ORI, R_RSP, -0x80000000);
   1265 
   1266 	// Kill the lower mapping
   1267 	x86_64_modri(c, OP_MOVI, R_RAX, 0);
   1268 	x86_64_modrm(c, OP_LEA, R_RDI, R_RBP, 0, 0, 64);
   1269 	x86_64_modrm(c, OP_STORE, R_RAX, R_RDI, 0, 0, 4096);
   1270 	x86_64_modrm(c, OP_STORE, R_RAX, R_RDI, 0, 0, 0);
   1271 	x86_64_modri(c, OP_ANDI, R_RDI, 0x7fffffff);
   1272 	x86_64_modrr(c, OP_WRCRR, R_CR3, R_RDI);
   1273 
   1274 	// Setup a call frame for _kstart
   1275 	x86_64_jmp(c, OP_JMP, done);
   1276 
   1277 	// hlt forever
   1278 	fixup_label(c, hang);
   1279 	x86_64_op(c, OP_CLI);
   1280 	x86_64_op(c, OP_HLT);
   1281 	x86_64_jmp(c, OP_JMP, hang);
   1282 
   1283 	// iret to long mode
   1284 	fixup_label(c, do_iret);
   1285 	x86_64_op(c, OP_IRET);
   1286 
   1287 	// ret to top half
   1288 	fixup_label(c, do_ret);
   1289 	x86_64_opr(c, OP_POPR, R_RAX);
   1290 	x86_64_modri(c, OP_ORI, R_RAX, -0x80000000);
   1291 	x86_64_opr(c, OP_PUSHR, R_RAX);
   1292 	x86_64_op(c, OP_RET);
   1293 
   1294 	// Setup a call frame for _kstart
   1295 	fixup_label(c, done);
   1296 	x86_64_modrr(c, OP_XORRM, R_RBP, R_RBP);
   1297 	x86_64_modrr(c, OP_MOVE, R_RDI, R_RBX);
   1298 	x86_64_opr(c, OP_PUSHR, R_RBP);
   1299 }
   1300 
   1301 func x86_64_output_ir(c: *compiler, d: *decl) {
   1302 	var ic: *irfunc;
   1303 
   1304 	ic = d.func_ir;
   1305 
   1306 	ic.c.filename = ic.filename;
   1307 	ic.c.lineno = ic.lineno;
   1308 	ic.c.colno = ic.colno;
   1309 	ic.s.filename = ic.filename;
   1310 	ic.s.lineno = ic.lineno;
   1311 
   1312 	fixup_label(c.s, d.func_label);
   1313 	add_symbol(c.s, d.name, d.func_label);
   1314 
   1315 	if strcmp(d.name, "_start") == 0 {
   1316 		x86_64_modrm(c.s, OP_LOAD, R_RDI, R_RSP, 0, 0, 0);
   1317 		x86_64_modrm(c.s, OP_LEA, R_RSI, R_RSP, 0, 0, 8);
   1318 		x86_64_modrm(c.s, OP_LEA, R_RDX, R_RSI, R_RDI, 8, 8);
   1319 		x86_64_opr(c.s, OP_PUSHR, R_RBP);
   1320 	} else if strcmp(d.name, "_kstart") == 0 {
   1321 		x86_64_kstart(c.s);
   1322 	}
   1323 
   1324 	//fputc(nil, '\n');
   1325 	//fputs(nil, d.name);
   1326 	//irshow(nil, ic.blocks[0]);
   1327 
   1328 	// Setup the frame
   1329 	x86_64_opr(ic.s, OP_PUSHR, R_RBP);
   1330 	x86_64_modrr(ic.s, OP_MOVE, R_RBP, R_RSP);
   1331 
   1332 	// Allocate local variables
   1333 	x86_64_output_irvars(ic);
   1334 
   1335 	// Output all blocks
   1336 	x86_64_output_irblock(ic, ic.blocks[0]);
   1337 
   1338 	// Clear the marks
   1339 	irreset(ic.blocks[0]);
   1340 }
   1341 
   1342 func x86_64_output_irvars(ic: *irfunc) {
   1343 	var offset: int;
   1344 	var size: int;
   1345 	var i: int;
   1346 	var v: *irvar;
   1347 
   1348 	// Allocate local variables
   1349 	offset = 0;
   1350 	i = 0;
   1351 	loop {
   1352 		if i == ic.vars_len {
   1353 			break;
   1354 		}
   1355 
   1356 		v = ic.vars[i];
   1357 
   1358 		if v.dead {
   1359 			i = i + 1;
   1360 			continue;
   1361 		}
   1362 
   1363 		if v.t && v.t.kind != TY_VOID {
   1364 			size = type_sizeof(ic.c, v.t);
   1365 		} else {
   1366 			size = sizeof(i);
   1367 		}
   1368 
   1369 		size = (size + 7) & -8;
   1370 
   1371 		offset = offset + size;
   1372 
   1373 		v.offset = -offset;
   1374 
   1375 		i = i + 1;
   1376 	}
   1377 
   1378 	// Zero initialize local variables
   1379 	if offset != 0 {
   1380 		x86_64_modri(ic.s, OP_SUBI, R_RSP, offset);
   1381 
   1382 		x86_64_modrr(ic.s, OP_XORRM, R_RAX, R_RAX);
   1383 
   1384 		i = 0;
   1385 		loop {
   1386 			if i == offset {
   1387 				break;
   1388 			}
   1389 
   1390 			i = i + 8;
   1391 
   1392 			x86_64_modrm(ic.s, OP_STORE, R_RAX, R_RBP, 0, 0, -i);
   1393 		}
   1394 	}
   1395 
   1396 	// Save parameters
   1397 	i = 0;
   1398 	loop {
   1399 		if i == ic.arg_count {
   1400 			break;
   1401 		}
   1402 
   1403 		v = ic.vars[i];
   1404 
   1405 		if i == 0 {
   1406 			x86_64_modrm(ic.s, OP_STORE, R_RDI, R_RBP, 0, 0, v.offset);
   1407 		} else if i == 1 {
   1408 			x86_64_modrm(ic.s, OP_STORE, R_RSI, R_RBP, 0, 0, v.offset);
   1409 		} else if i == 2 {
   1410 			x86_64_modrm(ic.s, OP_STORE, R_RDX, R_RBP, 0, 0, v.offset);
   1411 		} else if i == 3 {
   1412 			x86_64_modrm(ic.s, OP_STORE, R_RCX, R_RBP, 0, 0, v.offset);
   1413 		} else if i == 4 {
   1414 			x86_64_modrm(ic.s, OP_STORE, R_R8, R_RBP, 0, 0, v.offset);
   1415 		} else if i == 5 {
   1416 			x86_64_modrm(ic.s, OP_STORE, R_R9, R_RBP, 0, 0, v.offset);
   1417 		} else {
   1418 			// Stack argument
   1419 			x86_64_modrm(ic.s, OP_LOAD, R_RAX, R_RBP, 0, 0, (i - 6 + 2) * sizeof(i));
   1420 			x86_64_modrm(ic.s, OP_STORE, R_RAX, R_RBP, 0, 0, v.offset);
   1421 		}
   1422 
   1423 		i = i + 1;
   1424 	}
   1425 }
   1426 
   1427 func x86_64_output_irblock(ic: *irfunc, b: *irblock) {
   1428 	var op: *irop;
   1429 	var i: int;
   1430 
   1431 	b.mark = 1;
   1432 
   1433 	if !b.done {
   1434 		cdie(ic.c, "no return in function");
   1435 	}
   1436 
   1437 	fixup_label(ic.s, b.label);
   1438 
   1439 	i = 0;
   1440 	loop {
   1441 		if i == b.ops_len {
   1442 			break;
   1443 		}
   1444 
   1445 		op = b.ops[i];
   1446 
   1447 		x86_64_output_irstmt(ic, b, op);
   1448 
   1449 		i = i + 1;
   1450 	}
   1451 }
   1452 
   1453 func x86_64_output_irstmt(ic: *irfunc, b: *irblock, o: *irop) {
   1454 	var kind: int;
   1455 
   1456 	ic.c.filename = o.filename;
   1457 	ic.c.lineno = o.lineno;
   1458 	ic.c.colno = o.colno;
   1459 	ic.s.filename = o.filename;
   1460 	ic.s.lineno = o.lineno;
   1461 
   1462 	kind = o.kind;
   1463 	if kind == IOP_STORE {
   1464 		// Evaluate the address
   1465 		if o.a.kind == IOP_LOAD {
   1466 			x86_64_output_irexpr(ic, b, o.a.a);
   1467 		} else if o.a.kind == IOP_VAR {
   1468 			x86_64_modrm(ic.s, OP_LEA, R_RAX, R_RBP, 0, 0, ic.vars[o.a.n].offset);
   1469 		} else {
   1470 			die("invalid store");
   1471 		}
   1472 
   1473 		x86_64_opr(ic.s, OP_PUSHR, R_RAX);
   1474 
   1475 		// Evaluate the value
   1476 		x86_64_output_irexpr(ic, b, o.b);
   1477 
   1478 		x86_64_opr(ic.s, OP_POPR, R_RDI);
   1479 
   1480 		// Execute the store
   1481 		if o.t.kind == TY_BYTE {
   1482 			x86_64_modrm(ic.s, OP_STOREB, R_RAX, R_RDI, 0, 0, 0);
   1483 		} else if type_isprim(o.t) {
   1484 			x86_64_modrm(ic.s, OP_STORE, R_RAX, R_RDI, 0, 0, 0);
   1485 		} else {
   1486 			cdie(ic.c, "invalid store");
   1487 		}
   1488 	} else if kind == IOP_RETVAL {
   1489 		// Do nothing
   1490 	} else if kind == IOP_ARG {
   1491 		// Do nothing
   1492 	} else if kind == IOP_CALL {
   1493 		// Allocate some space for the arguments
   1494 		if o.n > 6 {
   1495 			x86_64_modri(ic.s, OP_SUBI, R_RSP, (o.n - 6) * sizeof(kind));
   1496 		}
   1497 
   1498 		// Setup arguments
   1499 		x86_64_output_irargs(ic, b, o);
   1500 
   1501 		// Call the function
   1502 		if o.a.kind == IOP_FUNC {
   1503 			x86_64_output_ircall(ic, b, o.a);
   1504 		} else {
   1505 			x86_64_output_irexpr(ic, b, o.a);
   1506 			x86_64_modr(ic.s, OP_ICALLM, R_RAX);
   1507 		}
   1508 
   1509 		// Release space reserved for the arguments
   1510 		if o.n > 6 {
   1511 			x86_64_modri(ic.s, OP_ADDI, R_RSP, (o.n - 6) * sizeof(kind));
   1512 		}
   1513 
   1514 		// Save the return value
   1515 		x86_64_output_irretval(ic, b, o);
   1516 
   1517 		if b.out.mark {
   1518 			x86_64_jmp(ic.s, OP_JMP, b.out.label);
   1519 		} else {
   1520 			x86_64_output_irblock(ic, b.out);
   1521 		}
   1522 		return;
   1523 	} else if kind == IOP_JUMP {
   1524 		if b.out.mark {
   1525 			// Jump to an already output block
   1526 			x86_64_jmp(ic.s, OP_JMP, b.out.label);
   1527 		} else {
   1528 			// Output a new block
   1529 			x86_64_output_irblock(ic, b.out);
   1530 		}
   1531 		return;
   1532 	} else if kind == IOP_BRANCH {
   1533 		// Evaluate the condition and branch if zero
   1534 		x86_64_output_irexpr(ic, b, o.a);
   1535 		x86_64_modrr(ic.s, OP_TESTRM, R_RAX, R_RAX);
   1536 		x86_64_jmp(ic.s, OP_JCC + CC_E, b.alt.label);
   1537 
   1538 		// Then jump to the output
   1539 		if b.out.mark {
   1540 			x86_64_jmp(ic.s, OP_JCC + CC_NE, b.out.label);
   1541 		} else {
   1542 			x86_64_output_irblock(ic, b.out);
   1543 		}
   1544 
   1545 		// And if we haven't already, output the alt branch
   1546 		if !b.alt.mark {
   1547 			x86_64_output_irblock(ic, b.alt);
   1548 		}
   1549 
   1550 		return;
   1551 	} else if kind == IOP_RETURN {
   1552 		// Evaluate the return expression and return
   1553 		if o.a {
   1554 			x86_64_output_irexpr(ic, b, o.a);
   1555 		}
   1556 
   1557 		x86_64_modrr(ic.s, OP_MOVE, R_RSP, R_RBP);
   1558 		x86_64_opr(ic.s, OP_POPR, R_RBP);
   1559 		x86_64_op(ic.s, OP_RET);
   1560 	} else {
   1561 		// Evaluate and discard the result
   1562 		x86_64_output_irexpr(ic, b, o);
   1563 	}
   1564 }
   1565 
   1566 func x86_64_output_irargs(ic: *irfunc, b: *irblock, o: *irop) {
   1567 	var i: int;
   1568 	var op: *irop;
   1569 
   1570 	i = 0;
   1571 	loop {
   1572 		if i == b.ops_len {
   1573 			return;
   1574 		}
   1575 
   1576 		op = b.ops[i];
   1577 		if op.kind == IOP_ARG {
   1578 			// Compute the value
   1579 			x86_64_output_irexpr(ic, b, op.a);
   1580 
   1581 			if op.n == 0 {
   1582 				x86_64_modrr(ic.s, OP_MOVE, R_RDI, R_RAX);
   1583 			} else if op.n == 1 {
   1584 				x86_64_modrr(ic.s, OP_MOVE, R_RSI, R_RAX);
   1585 			} else if op.n == 2 {
   1586 				x86_64_modrr(ic.s, OP_MOVE, R_RDX, R_RAX);
   1587 			} else if op.n == 3 {
   1588 				x86_64_modrr(ic.s, OP_MOVE, R_RCX, R_RAX);
   1589 			} else if op.n == 4 {
   1590 				x86_64_modrr(ic.s, OP_MOVE, R_R8, R_RAX);
   1591 			} else if op.n == 5 {
   1592 				x86_64_modrr(ic.s, OP_MOVE, R_R9, R_RAX);
   1593 			} else {
   1594 				// Stack argument
   1595 				x86_64_modrm(ic.s, OP_STORE, R_RAX, R_RSP, 0, 0, (op.n - 6) * sizeof(i));
   1596 			}
   1597 		}
   1598 
   1599 		i = i + 1;
   1600 	}
   1601 }
   1602 
   1603 func x86_64_output_irretval(ic: *irfunc, b: *irblock, o: *irop) {
   1604 	var i: int;
   1605 	var op: *irop;
   1606 
   1607 	// Find the retval place
   1608 	op = nil;
   1609 	i = 0;
   1610 	loop {
   1611 		if i == b.ops_len {
   1612 			return;
   1613 		}
   1614 
   1615 		op = b.ops[i];
   1616 		if op.kind == IOP_RETVAL {
   1617 			break;
   1618 		}
   1619 
   1620 		i = i + 1;
   1621 	}
   1622 
   1623 	// Do nothing if there was no return value
   1624 	if op.t.kind == TY_VOID {
   1625 		return;
   1626 	}
   1627 
   1628 	// Save the value
   1629 	x86_64_modrr(ic.s, OP_MOVE, R_RDI, R_RAX);
   1630 
   1631 	// Compute the address
   1632 	if op.a.kind == IOP_LOAD {
   1633 		x86_64_output_irexpr(ic, b, op.a.a);
   1634 	} else if op.a.kind == IOP_VAR {
   1635 		x86_64_modrm(ic.s, OP_LEA, R_RAX, R_RBP, 0, 0, ic.vars[op.a.n].offset);
   1636 	} else {
   1637 		die("invalid store");
   1638 	}
   1639 
   1640 	// Execute the store
   1641 	if op.t.kind == TY_BYTE {
   1642 		x86_64_modrm(ic.s, OP_STOREB, R_RDI, R_RAX, 0, 0, 0);
   1643 	} else if type_isprim(op.t) {
   1644 		x86_64_modrm(ic.s, OP_STORE, R_RDI, R_RAX, 0, 0, 0);
   1645 	} else {
   1646 		cdie(ic.c, "invalid store");
   1647 	}
   1648 }
   1649 
   1650 func x86_64_output_irstr(ic: *irfunc, b: *irblock, o: *irop) {
   1651 	var s: *label;
   1652 
   1653 	s = as_blob(ic.s, o.s, o.slen + 1);
   1654 
   1655 	reserve(ic.s, 16);
   1656 	x86_64_modrm(ic.s, OP_LEA, R_RAX, R_RIP, 0, 0, 128);
   1657 	addfixup(ic.s, s, FIXUP_DISP32);
   1658 }
   1659 
   1660 func x86_64_output_irfuncptr(ic: *irfunc, b: *irblock, o: *irop) {
   1661 	var d: *decl;
   1662 
   1663 	d = find(ic.c, o.s, nil, 0);
   1664 
   1665 	if !d || !d.func_defined {
   1666 		cdie(ic.c, "no such function");
   1667 	}
   1668 
   1669 	reserve(ic.s, 16);
   1670 	x86_64_modrm(ic.s, OP_LEA, R_RAX, R_RIP, 0, 0, 128);
   1671 	addfixup(ic.s, d.func_label, FIXUP_DISP32);
   1672 }
   1673 
   1674 func x86_64_output_ircall(ic: *irfunc, b: *irblock, o: *irop) {
   1675 	var d: *decl;
   1676 
   1677 	d = find(ic.c, o.s, nil, 0);
   1678 
   1679 	if !d || !d.func_defined {
   1680 		cdie(ic.c, "no such function");
   1681 	}
   1682 
   1683 	x86_64_jmp(ic.s, OP_CALL, d.func_label);
   1684 }
   1685 
   1686 func x86_64_output_irexpr(ic: *irfunc, b: *irblock, o: *irop) {
   1687 	var kind: int;
   1688 
   1689 	if !o {
   1690 		cdie(ic.c, "no expr");
   1691 	}
   1692 
   1693 	kind = o.kind;
   1694 	if kind == IOP_VAR {
   1695 		x86_64_modrm(ic.s, OP_LOAD, R_RAX, R_RBP, 0, 0, ic.vars[o.n].offset);
   1696 	} else if kind == IOP_VARREF {
   1697 		x86_64_modrm(ic.s, OP_LEA, R_RAX, R_RBP, 0, 0, ic.vars[o.n].offset);
   1698 	} else if kind == IOP_FUNC {
   1699 		x86_64_output_irfuncptr(ic, b, o);
   1700 	} else if kind == IOP_CONST {
   1701 		if o.n == 0 {
   1702 			x86_64_modrr(ic.s, OP_XORRM, R_RAX, R_RAX);
   1703 		} else if o.n < (-1 >> 33) && o.n >= (-1 << 31) {
   1704 			x86_64_modri(ic.s, OP_MOVI, R_RAX, o.n);
   1705 		} else {
   1706 			x86_64_opri64(ic.s, OP_MOVABS, R_RAX, o.n);
   1707 		}
   1708 	} else if kind == IOP_STR {
   1709 		x86_64_output_irstr(ic, b, o);
   1710 	} else if kind == IOP_LOAD {
   1711 		x86_64_output_irexpr(ic, b, o.a);
   1712 		if o.t.kind == TY_BYTE {
   1713 			x86_64_modrr(ic.s, OP_MOVE, R_RSI, R_RAX);
   1714 			x86_64_modrr(ic.s, OP_XORRM, R_RAX, R_RAX);
   1715 			x86_64_modrm(ic.s, OP_LOADB, R_RAX, R_RSI, 0, 0, 0);
   1716 		} else if type_isprim(o.t) {
   1717 			x86_64_modrm(ic.s, OP_LOAD, R_RAX, R_RAX, 0, 0, 0);
   1718 		} else {
   1719 			cdie(ic.c, "invalid load");
   1720 		}
   1721 	} else if kind == IOP_NEG {
   1722 		x86_64_output_irexpr(ic, b, o.a);
   1723 		x86_64_modr(ic.s, OP_NEGM, R_RAX);
   1724 	} else if kind == IOP_NOT {
   1725 		x86_64_output_irexpr(ic, b, o.a);
   1726 		x86_64_modr(ic.s, OP_NOTM, R_RAX);
   1727 	} else if kind == IOP_ADD {
   1728 		x86_64_output_irexpr(ic, b, o.b);
   1729 		x86_64_opr(ic.s, OP_PUSHR, R_RAX);
   1730 		x86_64_output_irexpr(ic, b, o.a);
   1731 		x86_64_opr(ic.s, OP_POPR, R_RCX);
   1732 		x86_64_modrr(ic.s, OP_ADDRM, R_RAX, R_RCX);
   1733 	} else if kind == IOP_AND {
   1734 		x86_64_output_irexpr(ic, b, o.b);
   1735 		x86_64_opr(ic.s, OP_PUSHR, R_RAX);
   1736 		x86_64_output_irexpr(ic, b, o.a);
   1737 		x86_64_opr(ic.s, OP_POPR, R_RCX);
   1738 		x86_64_modrr(ic.s, OP_ANDRM, R_RAX, R_RCX);
   1739 	} else if kind == IOP_OR {
   1740 		x86_64_output_irexpr(ic, b, o.b);
   1741 		x86_64_opr(ic.s, OP_PUSHR, R_RAX);
   1742 		x86_64_output_irexpr(ic, b, o.a);
   1743 		x86_64_opr(ic.s, OP_POPR, R_RCX);
   1744 		x86_64_modrr(ic.s, OP_ORRM, R_RAX, R_RCX);
   1745 	} else if kind == IOP_XOR {
   1746 		x86_64_output_irexpr(ic, b, o.b);
   1747 		x86_64_opr(ic.s, OP_PUSHR, R_RAX);
   1748 		x86_64_output_irexpr(ic, b, o.a);
   1749 		x86_64_opr(ic.s, OP_POPR, R_RCX);
   1750 		x86_64_modrr(ic.s, OP_XORRM, R_RAX, R_RCX);
   1751 	} else if kind == IOP_DIV {
   1752 		x86_64_output_irexpr(ic, b, o.b);
   1753 		x86_64_opr(ic.s, OP_PUSHR, R_RAX);
   1754 		x86_64_output_irexpr(ic, b, o.a);
   1755 		x86_64_opr(ic.s, OP_POPR, R_RCX);
   1756 		x86_64_modrr(ic.s, OP_XORRM, R_RDX, R_RDX);
   1757 		x86_64_modrr(ic.s, OP_TESTRM, R_RAX, R_RAX);
   1758 		x86_64_modrr(ic.s, OP_SETCC + CC_S, 0, R_RDX);
   1759 		x86_64_modr(ic.s, OP_NEGM, R_RDX);
   1760 		x86_64_modr(ic.s, OP_IDIVM, R_RCX);
   1761 	} else if kind == IOP_MOD {
   1762 		x86_64_output_irexpr(ic, b, o.b);
   1763 		x86_64_opr(ic.s, OP_PUSHR, R_RAX);
   1764 		x86_64_output_irexpr(ic, b, o.a);
   1765 		x86_64_opr(ic.s, OP_POPR, R_RCX);
   1766 		x86_64_modrr(ic.s, OP_XORRM, R_RDX, R_RDX);
   1767 		x86_64_modrr(ic.s, OP_TESTRM, R_RAX, R_RAX);
   1768 		x86_64_modrr(ic.s, OP_SETCC + CC_S, 0, R_RDX);
   1769 		x86_64_modr(ic.s, OP_NEGM, R_RDX);
   1770 		x86_64_modr(ic.s, OP_IDIVM, R_RCX);
   1771 		x86_64_modrr(ic.s, OP_MOVE, R_RAX, R_RDX);
   1772 	} else if kind == IOP_LSH {
   1773 		x86_64_output_irexpr(ic, b, o.b);
   1774 		x86_64_opr(ic.s, OP_PUSHR, R_RAX);
   1775 		x86_64_output_irexpr(ic, b, o.a);
   1776 		x86_64_opr(ic.s, OP_POPR, R_RCX);
   1777 		x86_64_modr(ic.s, OP_SHLM, R_RAX);
   1778 	} else if kind == IOP_RSH {
   1779 		x86_64_output_irexpr(ic, b, o.b);
   1780 		x86_64_opr(ic.s, OP_PUSHR, R_RAX);
   1781 		x86_64_output_irexpr(ic, b, o.a);
   1782 		x86_64_opr(ic.s, OP_POPR, R_RCX);
   1783 		x86_64_modr(ic.s, OP_SHRM, R_RAX);
   1784 	} else if kind == IOP_MUL {
   1785 		x86_64_output_irexpr(ic, b, o.b);
   1786 		x86_64_opr(ic.s, OP_PUSHR, R_RAX);
   1787 		x86_64_output_irexpr(ic, b, o.a);
   1788 		x86_64_opr(ic.s, OP_POPR, R_RCX);
   1789 		x86_64_modr(ic.s, OP_IMULM, R_RCX);
   1790 	} else if kind == IOP_SUB {
   1791 		x86_64_output_irexpr(ic, b, o.b);
   1792 		x86_64_opr(ic.s, OP_PUSHR, R_RAX);
   1793 		x86_64_output_irexpr(ic, b, o.a);
   1794 		x86_64_opr(ic.s, OP_POPR, R_RCX);
   1795 		x86_64_modrr(ic.s, OP_SUBRM, R_RAX, R_RCX);
   1796 	} else if kind == IOP_EQ {
   1797 		x86_64_output_irexpr(ic, b, o.b);
   1798 		x86_64_opr(ic.s, OP_PUSHR, R_RAX);
   1799 		x86_64_output_irexpr(ic, b, o.a);
   1800 		x86_64_opr(ic.s, OP_POPR, R_RCX);
   1801 		x86_64_modrr(ic.s, OP_MOVE, R_RDX, R_RAX);
   1802 		x86_64_modrr(ic.s, OP_XORRM, R_RAX, R_RAX);
   1803 		x86_64_modrr(ic.s, OP_CMPRM, R_RDX, R_RCX);
   1804 		x86_64_modrr(ic.s, OP_SETCC + CC_E, 0, R_RAX);
   1805 	} else if kind == IOP_NE {
   1806 		x86_64_output_irexpr(ic, b, o.b);
   1807 		x86_64_opr(ic.s, OP_PUSHR, R_RAX);
   1808 		x86_64_output_irexpr(ic, b, o.a);
   1809 		x86_64_opr(ic.s, OP_POPR, R_RCX);
   1810 		x86_64_modrr(ic.s, OP_MOVE, R_RDX, R_RAX);
   1811 		x86_64_modrr(ic.s, OP_XORRM, R_RAX, R_RAX);
   1812 		x86_64_modrr(ic.s, OP_CMPRM, R_RDX, R_RCX);
   1813 		x86_64_modrr(ic.s, OP_SETCC + CC_NE, 0, R_RAX);
   1814 	} else if kind == IOP_GT {
   1815 		x86_64_output_irexpr(ic, b, o.b);
   1816 		x86_64_opr(ic.s, OP_PUSHR, R_RAX);
   1817 		x86_64_output_irexpr(ic, b, o.a);
   1818 		x86_64_opr(ic.s, OP_POPR, R_RCX);
   1819 		x86_64_modrr(ic.s, OP_MOVE, R_RDX, R_RAX);
   1820 		x86_64_modrr(ic.s, OP_XORRM, R_RAX, R_RAX);
   1821 		x86_64_modrr(ic.s, OP_CMPRM, R_RDX, R_RCX);
   1822 		x86_64_modrr(ic.s, OP_SETCC + CC_G, 0, R_RAX);
   1823 	} else if kind == IOP_GE {
   1824 		x86_64_output_irexpr(ic, b, o.b);
   1825 		x86_64_opr(ic.s, OP_PUSHR, R_RAX);
   1826 		x86_64_output_irexpr(ic, b, o.a);
   1827 		x86_64_opr(ic.s, OP_POPR, R_RCX);
   1828 		x86_64_modrr(ic.s, OP_MOVE, R_RDX, R_RAX);
   1829 		x86_64_modrr(ic.s, OP_XORRM, R_RAX, R_RAX);
   1830 		x86_64_modrr(ic.s, OP_CMPRM, R_RDX, R_RCX);
   1831 		x86_64_modrr(ic.s, OP_SETCC + CC_GE, 0, R_RAX);
   1832 	} else if kind == IOP_LT {
   1833 		x86_64_output_irexpr(ic, b, o.b);
   1834 		x86_64_opr(ic.s, OP_PUSHR, R_RAX);
   1835 		x86_64_output_irexpr(ic, b, o.a);
   1836 		x86_64_opr(ic.s, OP_POPR, R_RCX);
   1837 		x86_64_modrr(ic.s, OP_MOVE, R_RDX, R_RAX);
   1838 		x86_64_modrr(ic.s, OP_XORRM, R_RAX, R_RAX);
   1839 		x86_64_modrr(ic.s, OP_CMPRM, R_RDX, R_RCX);
   1840 		x86_64_modrr(ic.s, OP_SETCC + CC_L, 0, R_RAX);
   1841 	} else if kind == IOP_LE {
   1842 		x86_64_output_irexpr(ic, b, o.b);
   1843 		x86_64_opr(ic.s, OP_PUSHR, R_RAX);
   1844 		x86_64_output_irexpr(ic, b, o.a);
   1845 		x86_64_opr(ic.s, OP_POPR, R_RCX);
   1846 		x86_64_modrr(ic.s, OP_MOVE, R_RDX, R_RAX);
   1847 		x86_64_modrr(ic.s, OP_XORRM, R_RAX, R_RAX);
   1848 		x86_64_modrr(ic.s, OP_CMPRM, R_RDX, R_RCX);
   1849 		x86_64_modrr(ic.s, OP_SETCC + CC_LE, 0, R_RAX);
   1850 	} else {
   1851 		cdie(ic.c, "invalid op");
   1852 	}
   1853 }