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      1 // Copyright 2009 The Go Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style
      3 // license that can be found in the LICENSE file.
      4 
      5 #include "go_asm.h"
      6 #include "go_tls.h"
      7 #include "textflag.h"
      8 
      9 // void runtimeasmstdcall(void *c);
     10 TEXT runtimeasmstdcall(SB),NOSPLIT,$0
     11 	MOVL	fn+0(FP), BX
     12 
     13 	// SetLastError(0).
     14 	MOVL	$0, 0x34(FS)
     15 
     16 	// Copy args to the stack.
     17 	MOVL	SP, BP
     18 	MOVL	libcall_n(BX), CX	// words
     19 	MOVL	CX, AX
     20 	SALL	$2, AX
     21 	SUBL	AX, SP			// room for args
     22 	MOVL	SP, DI
     23 	MOVL	libcall_args(BX), SI
     24 	CLD
     25 	REP; MOVSL
     26 
     27 	// Call stdcall or cdecl function.
     28 	// DI SI BP BX are preserved, SP is not
     29 	CALL	libcall_fn(BX)
     30 	MOVL	BP, SP
     31 
     32 	// Return result.
     33 	MOVL	fn+0(FP), BX
     34 	MOVL	AX, libcall_r1(BX)
     35 	MOVL	DX, libcall_r2(BX)
     36 
     37 	// GetLastError().
     38 	MOVL	0x34(FS), AX
     39 	MOVL	AX, libcall_err(BX)
     40 
     41 	RET
     42 
     43 TEXT	runtimebadsignal2(SB),NOSPLIT,$24
     44 	// stderr
     45 	MOVL	$-12, 0(SP)
     46 	MOVL	SP, BP
     47 	CALL	*runtime_GetStdHandle(SB)
     48 	MOVL	BP, SP
     49 
     50 	MOVL	AX, 0(SP)	// handle
     51 	MOVL	$runtimebadsignalmsg(SB), DX // pointer
     52 	MOVL	DX, 4(SP)
     53 	MOVL	runtimebadsignallen(SB), DX // count
     54 	MOVL	DX, 8(SP)
     55 	LEAL	20(SP), DX  // written count
     56 	MOVL	$0, 0(DX)
     57 	MOVL	DX, 12(SP)
     58 	MOVL	$0, 16(SP) // overlapped
     59 	CALL	*runtime_WriteFile(SB)
     60 	MOVL	BP, SI
     61 	RET
     62 
     63 // faster get/set last error
     64 TEXT runtimegetlasterror(SB),NOSPLIT,$0
     65 	MOVL	0x34(FS), AX
     66 	MOVL	AX, ret+0(FP)
     67 	RET
     68 
     69 TEXT runtimesetlasterror(SB),NOSPLIT,$0
     70 	MOVL	err+0(FP), AX
     71 	MOVL	AX, 0x34(FS)
     72 	RET
     73 
     74 // Called by Windows as a Vectored Exception Handler (VEH).
     75 // First argument is pointer to struct containing
     76 // exception record and context pointers.
     77 // Handler function is stored in AX.
     78 // Return 0 for 'not handled', -1 for handled.
     79 TEXT runtimesigtramp(SB),NOSPLIT,$0-0
     80 	MOVL	ptrs+0(FP), CX
     81 	SUBL	$40, SP
     82 
     83 	// save callee-saved registers
     84 	MOVL	BX, 28(SP)
     85 	MOVL	BP, 16(SP)
     86 	MOVL	SI, 20(SP)
     87 	MOVL	DI, 24(SP)
     88 
     89 	MOVL	AX, SI	// save handler address
     90 
     91 	// find g
     92 	get_tls(DX)
     93 	CMPL	DX, $0
     94 	JNE	3(PC)
     95 	MOVL	$0, AX // continue
     96 	JMP	done
     97 	MOVL	g(DX), DX
     98 	CMPL	DX, $0
     99 	JNE	2(PC)
    100 	CALL	runtimebadsignal2(SB)
    101 
    102 	// save g and SP in case of stack switch
    103 	MOVL	DX, 32(SP)	// g
    104 	MOVL	SP, 36(SP)
    105 
    106 	// do we need to switch to the g0 stack?
    107 	MOVL	g_m(DX), BX
    108 	MOVL	m_g0(BX), BX
    109 	CMPL	DX, BX
    110 	JEQ	g0
    111 
    112 	// switch to the g0 stack
    113 	get_tls(BP)
    114 	MOVL	BX, g(BP)
    115 	MOVL	(g_sched+gobuf_sp)(BX), DI
    116 	// make it look like mstart called us on g0, to stop traceback
    117 	SUBL	$4, DI
    118 	MOVL	$runtimemstart(SB), 0(DI)
    119 	// traceback will think that we've done SUBL
    120 	// on this stack, so subtract them here to match.
    121 	// (we need room for sighandler arguments anyway).
    122 	// and re-save old SP for restoring later.
    123 	SUBL	$40, DI
    124 	MOVL	SP, 36(DI)
    125 	MOVL	DI, SP
    126 
    127 g0:
    128 	MOVL	0(CX), BX // ExceptionRecord*
    129 	MOVL	4(CX), CX // Context*
    130 	MOVL	BX, 0(SP)
    131 	MOVL	CX, 4(SP)
    132 	MOVL	DX, 8(SP)
    133 	CALL	SI	// call handler
    134 	// AX is set to report result back to Windows
    135 	MOVL	12(SP), AX
    136 
    137 	// switch back to original stack and g
    138 	// no-op if we never left.
    139 	MOVL	36(SP), SP
    140 	MOVL	32(SP), DX
    141 	get_tls(BP)
    142 	MOVL	DX, g(BP)
    143 
    144 done:
    145 	// restore callee-saved registers
    146 	MOVL	24(SP), DI
    147 	MOVL	20(SP), SI
    148 	MOVL	16(SP), BP
    149 	MOVL	28(SP), BX
    150 
    151 	ADDL	$40, SP
    152 	// RET 4 (return and pop 4 bytes parameters)
    153 	BYTE $0xC2; WORD $4
    154 	RET // unreached; make assembler happy
    155 
    156 TEXT runtimeexceptiontramp(SB),NOSPLIT,$0
    157 	MOVL	$runtimeexceptionhandler(SB), AX
    158 	JMP	runtimesigtramp(SB)
    159 
    160 TEXT runtimefirstcontinuetramp(SB),NOSPLIT,$0-0
    161 	// is never called
    162 	INT	$3
    163 
    164 TEXT runtimelastcontinuetramp(SB),NOSPLIT,$0-0
    165 	MOVL	$runtimelastcontinuehandler(SB), AX
    166 	JMP	runtimesigtramp(SB)
    167 
    168 TEXT runtimectrlhandler(SB),NOSPLIT,$0
    169 	PUSHL	$runtimectrlhandler1(SB)
    170 	CALL	runtimeexternalthreadhandler(SB)
    171 	MOVL	4(SP), CX
    172 	ADDL	$12, SP
    173 	JMP	CX
    174 
    175 TEXT runtimeprofileloop(SB),NOSPLIT,$0
    176 	PUSHL	$runtimeprofileloop1(SB)
    177 	CALL	runtimeexternalthreadhandler(SB)
    178 	MOVL	4(SP), CX
    179 	ADDL	$12, SP
    180 	JMP	CX
    181 
    182 TEXT runtimeexternalthreadhandler(SB),NOSPLIT,$0
    183 	PUSHL	BP
    184 	MOVL	SP, BP
    185 	PUSHL	BX
    186 	PUSHL	SI
    187 	PUSHL	DI
    188 	PUSHL	0x14(FS)
    189 	MOVL	SP, DX
    190 
    191 	// setup dummy m, g
    192 	SUBL	$m__size, SP		// space for M
    193 	MOVL	SP, 0(SP)
    194 	MOVL	$m__size, 4(SP)
    195 	CALL	runtimememclrNoHeapPointers(SB)	// smashes AX,BX,CX
    196 
    197 	LEAL	m_tls(SP), CX
    198 	MOVL	CX, 0x14(FS)
    199 	MOVL	SP, BX
    200 	SUBL	$g__size, SP		// space for G
    201 	MOVL	SP, g(CX)
    202 	MOVL	SP, m_g0(BX)
    203 
    204 	MOVL	SP, 0(SP)
    205 	MOVL	$g__size, 4(SP)
    206 	CALL	runtimememclrNoHeapPointers(SB)	// smashes AX,BX,CX
    207 	LEAL	g__size(SP), BX
    208 	MOVL	BX, g_m(SP)
    209 
    210 	LEAL	-32768(SP), CX		// must be less than SizeOfStackReserve set by linker
    211 	MOVL	CX, (g_stack+stack_lo)(SP)
    212 	ADDL	$const__StackGuard, CX
    213 	MOVL	CX, g_stackguard0(SP)
    214 	MOVL	CX, g_stackguard1(SP)
    215 	MOVL	DX, (g_stack+stack_hi)(SP)
    216 
    217 	PUSHL	AX			// room for return value
    218 	PUSHL	16(BP)			// arg for handler
    219 	CALL	8(BP)
    220 	POPL	CX
    221 	POPL	AX			// pass return value to Windows in AX
    222 
    223 	get_tls(CX)
    224 	MOVL	g(CX), CX
    225 	MOVL	(g_stack+stack_hi)(CX), SP
    226 	POPL	0x14(FS)
    227 	POPL	DI
    228 	POPL	SI
    229 	POPL	BX
    230 	POPL	BP
    231 	RET
    232 
    233 GLOBL runtimecbctxts(SB), NOPTR, $4
    234 
    235 TEXT runtimecallbackasm1+0(SB),NOSPLIT,$0
    236   	MOVL	0(SP), AX	// will use to find our callback context
    237 
    238 	// remove return address from stack, we are not returning there
    239 	ADDL	$4, SP
    240 
    241 	// address to callback parameters into CX
    242 	LEAL	4(SP), CX
    243 
    244 	// save registers as required for windows callback
    245 	PUSHL	DI
    246 	PUSHL	SI
    247 	PUSHL	BP
    248 	PUSHL	BX
    249 
    250 	// determine index into runtimecbctxts table
    251 	SUBL	$runtimecallbackasm(SB), AX
    252 	MOVL	$0, DX
    253 	MOVL	$5, BX	// divide by 5 because each call instruction in runtimecallbacks is 5 bytes long
    254 	DIVL	BX
    255 
    256 	// find correspondent runtimecbctxts table entry
    257 	MOVL	runtimecbctxts(SB), BX
    258 	MOVL	-4(BX)(AX*4), BX
    259 
    260 	// extract callback context
    261 	MOVL	wincallbackcontext_gobody(BX), AX
    262 	MOVL	wincallbackcontext_argsize(BX), DX
    263 
    264 	// preserve whatever's at the memory location that
    265 	// the callback will use to store the return value
    266 	PUSHL	0(CX)(DX*1)
    267 
    268 	// extend argsize by size of return value
    269 	ADDL	$4, DX
    270 
    271 	// remember how to restore stack on return
    272 	MOVL	wincallbackcontext_restorestack(BX), BX
    273 	PUSHL	BX
    274 
    275 	// call target Go function
    276 	PUSHL	DX			// argsize (including return value)
    277 	PUSHL	CX			// callback parameters
    278 	PUSHL	AX			// address of target Go function
    279 	CLD
    280 	CALL	runtimecgocallback_gofunc(SB)
    281 	POPL	AX
    282 	POPL	CX
    283 	POPL	DX
    284 
    285 	// how to restore stack on return
    286 	POPL	BX
    287 
    288 	// return value into AX (as per Windows spec)
    289 	// and restore previously preserved value
    290 	MOVL	-4(CX)(DX*1), AX
    291 	POPL	-4(CX)(DX*1)
    292 
    293 	MOVL	BX, CX			// cannot use BX anymore
    294 
    295 	// restore registers as required for windows callback
    296 	POPL	BX
    297 	POPL	BP
    298 	POPL	SI
    299 	POPL	DI
    300 
    301 	// remove callback parameters before return (as per Windows spec)
    302 	POPL	DX
    303 	ADDL	CX, SP
    304 	PUSHL	DX
    305 
    306 	CLD
    307 
    308 	RET
    309 
    310 // void tstart(M *newm);
    311 TEXT runtimetstart(SB),NOSPLIT,$0
    312 	MOVL	newm+0(FP), CX		// m
    313 	MOVL	m_g0(CX), DX		// g
    314 
    315 	// Layout new m scheduler stack on os stack.
    316 	MOVL	SP, AX
    317 	MOVL	AX, (g_stack+stack_hi)(DX)
    318 	SUBL	$(64*1024), AX		// stack size
    319 	MOVL	AX, (g_stack+stack_lo)(DX)
    320 	ADDL	$const__StackGuard, AX
    321 	MOVL	AX, g_stackguard0(DX)
    322 	MOVL	AX, g_stackguard1(DX)
    323 
    324 	// Set up tls.
    325 	LEAL	m_tls(CX), SI
    326 	MOVL	SI, 0x14(FS)
    327 	MOVL	CX, g_m(DX)
    328 	MOVL	DX, g(SI)
    329 
    330 	// Someday the convention will be D is always cleared.
    331 	CLD
    332 
    333 	CALL	runtimestackcheck(SB)	// clobbers AX,CX
    334 	CALL	runtimemstart(SB)
    335 
    336 	RET
    337 
    338 // uint32 tstart_stdcall(M *newm);
    339 TEXT runtimetstart_stdcall(SB),NOSPLIT,$0
    340 	MOVL	newm+0(FP), BX
    341 
    342 	PUSHL	BX
    343 	CALL	runtimetstart(SB)
    344 	POPL	BX
    345 
    346 	// Adjust stack for stdcall to return properly.
    347 	MOVL	(SP), AX		// save return address
    348 	ADDL	$4, SP			// remove single parameter
    349 	MOVL	AX, (SP)		// restore return address
    350 
    351 	XORL	AX, AX			// return 0 == success
    352 
    353 	RET
    354 
    355 // setldt(int entry, int address, int limit)
    356 TEXT runtimesetldt(SB),NOSPLIT,$0
    357 	MOVL	address+4(FP), CX
    358 	MOVL	CX, 0x14(FS)
    359 	RET
    360 
    361 // onosstack calls fn on OS stack.
    362 // func onosstack(fn unsafe.Pointer, arg uint32)
    363 TEXT runtimeonosstack(SB),NOSPLIT,$0
    364 	MOVL	fn+0(FP), AX		// to hide from 8l
    365 	MOVL	arg+4(FP), BX
    366 
    367 	// Execute call on m->g0 stack, in case we are not actually
    368 	// calling a system call wrapper, like when running under WINE.
    369 	get_tls(CX)
    370 	CMPL	CX, $0
    371 	JNE	3(PC)
    372 	// Not a Go-managed thread. Do not switch stack.
    373 	CALL	AX
    374 	RET
    375 
    376 	MOVL	g(CX), BP
    377 	MOVL	g_m(BP), BP
    378 
    379 	// leave pc/sp for cpu profiler
    380 	MOVL	(SP), SI
    381 	MOVL	SI, m_libcallpc(BP)
    382 	MOVL	g(CX), SI
    383 	MOVL	SI, m_libcallg(BP)
    384 	// sp must be the last, because once async cpu profiler finds
    385 	// all three values to be non-zero, it will use them
    386 	LEAL	usec+0(FP), SI
    387 	MOVL	SI, m_libcallsp(BP)
    388 
    389 	MOVL	m_g0(BP), SI
    390 	CMPL	g(CX), SI
    391 	JNE	switch
    392 	// executing on m->g0 already
    393 	CALL	AX
    394 	JMP	ret
    395 
    396 switch:
    397 	// Switch to m->g0 stack and back.
    398 	MOVL	(g_sched+gobuf_sp)(SI), SI
    399 	MOVL	SP, -4(SI)
    400 	LEAL	-4(SI), SP
    401 	CALL	AX
    402 	MOVL	0(SP), SP
    403 
    404 ret:
    405 	get_tls(CX)
    406 	MOVL	g(CX), BP
    407 	MOVL	g_m(BP), BP
    408 	MOVL	$0, m_libcallsp(BP)
    409 	RET
    410 
    411 // Runs on OS stack. duration (in 100ns units) is in BX.
    412 TEXT runtimeusleep2(SB),NOSPLIT,$20
    413 	// Want negative 100ns units.
    414 	NEGL	BX
    415 	MOVL	$-1, hi-4(SP)
    416 	MOVL	BX, lo-8(SP)
    417 	LEAL	lo-8(SP), BX
    418 	MOVL	BX, ptime-12(SP)
    419 	MOVL	$0, alertable-16(SP)
    420 	MOVL	$-1, handle-20(SP)
    421 	MOVL	SP, BP
    422 	MOVL	runtime_NtWaitForSingleObject(SB), AX
    423 	CALL	AX
    424 	MOVL	BP, SP
    425 	RET
    426 
    427 // Runs on OS stack.
    428 TEXT runtimeswitchtothread(SB),NOSPLIT,$0
    429 	MOVL	SP, BP
    430 	MOVL	runtime_SwitchToThread(SB), AX
    431 	CALL	AX
    432 	MOVL	BP, SP
    433 	RET
    434 
    435 // See http://www.dcl.hpi.uni-potsdam.de/research/WRK/2007/08/getting-os-information-the-kuser_shared_data-structure/
    436 // Must read hi1, then lo, then hi2. The snapshot is valid if hi1 == hi2.
    437 #define _INTERRUPT_TIME 0x7ffe0008
    438 #define _SYSTEM_TIME 0x7ffe0014
    439 #define time_lo 0
    440 #define time_hi1 4
    441 #define time_hi2 8
    442 
    443 TEXT runtimenanotime(SB),NOSPLIT,$0-8
    444 	CMPB	runtimeuseQPCTime(SB), $0
    445 	JNE	useQPC
    446 loop:
    447 	MOVL	(_INTERRUPT_TIME+time_hi1), AX
    448 	MOVL	(_INTERRUPT_TIME+time_lo), CX
    449 	MOVL	(_INTERRUPT_TIME+time_hi2), DI
    450 	CMPL	AX, DI
    451 	JNE	loop
    452 
    453 	// wintime = DI:CX, multiply by 100
    454 	MOVL	$100, AX
    455 	MULL	CX
    456 	IMULL	$100, DI
    457 	ADDL	DI, DX
    458 	// wintime*100 = DX:AX, subtract startNano and return
    459 	SUBL	runtimestartNano+0(SB), AX
    460 	SBBL	runtimestartNano+4(SB), DX
    461 	MOVL	AX, ret_lo+0(FP)
    462 	MOVL	DX, ret_hi+4(FP)
    463 	RET
    464 useQPC:
    465 	JMP	runtimenanotimeQPC(SB)
    466 	RET
    467 
    468 TEXT timenow(SB),NOSPLIT,$0-20
    469 	CMPB	runtimeuseQPCTime(SB), $0
    470 	JNE	useQPC
    471 loop:
    472 	MOVL	(_INTERRUPT_TIME+time_hi1), AX
    473 	MOVL	(_INTERRUPT_TIME+time_lo), CX
    474 	MOVL	(_INTERRUPT_TIME+time_hi2), DI
    475 	CMPL	AX, DI
    476 	JNE	loop
    477 
    478 	// w = DI:CX
    479 	// multiply by 100
    480 	MOVL	$100, AX
    481 	MULL	CX
    482 	IMULL	$100, DI
    483 	ADDL	DI, DX
    484 	// w*100 = DX:AX
    485 	// subtract startNano and save for return
    486 	SUBL	runtimestartNano+0(SB), AX
    487 	SBBL	runtimestartNano+4(SB), DX
    488 	MOVL	AX, mono+12(FP)
    489 	MOVL	DX, mono+16(FP)
    490 
    491 wall:
    492 	MOVL	(_SYSTEM_TIME+time_hi1), CX
    493 	MOVL	(_SYSTEM_TIME+time_lo), AX
    494 	MOVL	(_SYSTEM_TIME+time_hi2), DX
    495 	CMPL	CX, DX
    496 	JNE	wall
    497 
    498 	// w = DX:AX
    499 	// convert to Unix epoch (but still 100ns units)
    500 	#define delta 116444736000000000
    501 	SUBL	$(delta & 0xFFFFFFFF), AX
    502 	SBBL $(delta >> 32), DX
    503 
    504 	// nano/100 = DX:AX
    505 	// split into two decimal halves by div 1e9.
    506 	// (decimal point is two spots over from correct place,
    507 	// but we avoid overflow in the high word.)
    508 	MOVL	$1000000000, CX
    509 	DIVL	CX
    510 	MOVL	AX, DI
    511 	MOVL	DX, SI
    512 
    513 	// DI = nano/100/1e9 = nano/1e11 = sec/100, DX = SI = nano/100%1e9
    514 	// split DX into seconds and nanoseconds by div 1e7 magic multiply.
    515 	MOVL	DX, AX
    516 	MOVL	$1801439851, CX
    517 	MULL	CX
    518 	SHRL	$22, DX
    519 	MOVL	DX, BX
    520 	IMULL	$10000000, DX
    521 	MOVL	SI, CX
    522 	SUBL	DX, CX
    523 
    524 	// DI = sec/100 (still)
    525 	// BX = (nano/100%1e9)/1e7 = (nano/1e9)%100 = sec%100
    526 	// CX = (nano/100%1e9)%1e7 = (nano%1e9)/100 = nsec/100
    527 	// store nsec for return
    528 	IMULL	$100, CX
    529 	MOVL	CX, nsec+8(FP)
    530 
    531 	// DI = sec/100 (still)
    532 	// BX = sec%100
    533 	// construct DX:AX = 64-bit sec and store for return
    534 	MOVL	$0, DX
    535 	MOVL	$100, AX
    536 	MULL	DI
    537 	ADDL	BX, AX
    538 	ADCL	$0, DX
    539 	MOVL	AX, sec+0(FP)
    540 	MOVL	DX, sec+4(FP)
    541 	RET
    542 useQPC:
    543 	JMP	runtimenowQPC(SB)
    544 	RET
    545