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go/src/runtime/asm_386.s
Tobias Klauser e0ac5f540b runtime: use internal/cpu instead of support_avx 
After CL 104636 cpu.X86.HasAVX is set early enough that it can be used
to determine useAVXmemmove. Use it and remove support_avx.

Change-Id: Ib7a627bede2bf96c92362507e742bd833cb42a74
Reviewed-on: https://go-review.googlesource.com/106235
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2018-04-11 13:50:04 +00:00

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36 KiB
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// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
#include "go_asm.h"
#include "go_tls.h"
#include "funcdata.h"
#include "textflag.h"
// _rt0_386 is common startup code for most 386 systems when using
// internal linking. This is the entry point for the program from the
// kernel for an ordinary -buildmode=exe program. The stack holds the
// number of arguments and the C-style argv.
TEXT _rt0_386(SB),NOSPLIT,$8
MOVL 8(SP), AX // argc
LEAL 12(SP), BX // argv
MOVL AX, 0(SP)
MOVL BX, 4(SP)
JMP runtime·rt0_go(SB)
// _rt0_386_lib is common startup code for most 386 systems when
// using -buildmode=c-archive or -buildmode=c-shared. The linker will
// arrange to invoke this function as a global constructor (for
// c-archive) or when the shared library is loaded (for c-shared).
// We expect argc and argv to be passed on the stack following the
// usual C ABI.
TEXT _rt0_386_lib(SB),NOSPLIT,$0
PUSHL BP
MOVL SP, BP
PUSHL BX
PUSHL SI
PUSHL DI
MOVL 8(BP), AX
MOVL AX, _rt0_386_lib_argc<>(SB)
MOVL 12(BP), AX
MOVL AX, _rt0_386_lib_argv<>(SB)
// Synchronous initialization.
CALL runtime·libpreinit(SB)
SUBL $8, SP
// Create a new thread to do the runtime initialization.
MOVL _cgo_sys_thread_create(SB), AX
TESTL AX, AX
JZ nocgo
// Align stack to call C function.
// We moved SP to BP above, but BP was clobbered by the libpreinit call.
MOVL SP, BP
ANDL $~15, SP
MOVL $_rt0_386_lib_go(SB), BX
MOVL BX, 0(SP)
MOVL $0, 4(SP)
CALL AX
MOVL BP, SP
JMP restore
nocgo:
MOVL $0x800000, 0(SP) // stacksize = 8192KB
MOVL $_rt0_386_lib_go(SB), AX
MOVL AX, 4(SP) // fn
CALL runtime·newosproc0(SB)
restore:
ADDL $8, SP
POPL DI
POPL SI
POPL BX
POPL BP
RET
// _rt0_386_lib_go initializes the Go runtime.
// This is started in a separate thread by _rt0_386_lib.
TEXT _rt0_386_lib_go(SB),NOSPLIT,$8
MOVL _rt0_386_lib_argc<>(SB), AX
MOVL AX, 0(SP)
MOVL _rt0_386_lib_argv<>(SB), AX
MOVL AX, 4(SP)
JMP runtime·rt0_go(SB)
DATA _rt0_386_lib_argc<>(SB)/4, $0
GLOBL _rt0_386_lib_argc<>(SB),NOPTR, $4
DATA _rt0_386_lib_argv<>(SB)/4, $0
GLOBL _rt0_386_lib_argv<>(SB),NOPTR, $4
TEXT runtime·rt0_go(SB),NOSPLIT,$0
// Copy arguments forward on an even stack.
// Users of this function jump to it, they don't call it.
MOVL 0(SP), AX
MOVL 4(SP), BX
SUBL $128, SP // plenty of scratch
ANDL $~15, SP
MOVL AX, 120(SP) // save argc, argv away
MOVL BX, 124(SP)
// set default stack bounds.
// _cgo_init may update stackguard.
MOVL $runtime·g0(SB), BP
LEAL (-64*1024+104)(SP), BX
MOVL BX, g_stackguard0(BP)
MOVL BX, g_stackguard1(BP)
MOVL BX, (g_stack+stack_lo)(BP)
MOVL SP, (g_stack+stack_hi)(BP)
// find out information about the processor we're on
#ifdef GOOS_nacl // NaCl doesn't like PUSHFL/POPFL
JMP has_cpuid
#else
// first see if CPUID instruction is supported.
PUSHFL
PUSHFL
XORL $(1<<21), 0(SP) // flip ID bit
POPFL
PUSHFL
POPL AX
XORL 0(SP), AX
POPFL // restore EFLAGS
TESTL $(1<<21), AX
JNE has_cpuid
#endif
bad_proc: // show that the program requires MMX.
MOVL $2, 0(SP)
MOVL $bad_proc_msg<>(SB), 4(SP)
MOVL $0x3d, 8(SP)
CALL runtime·write(SB)
MOVL $1, 0(SP)
CALL runtime·exit(SB)
CALL runtime·abort(SB)
has_cpuid:
MOVL $0, AX
CPUID
MOVL AX, SI
CMPL AX, $0
JE nocpuinfo
// Figure out how to serialize RDTSC.
// On Intel processors LFENCE is enough. AMD requires MFENCE.
// Don't know about the rest, so let's do MFENCE.
CMPL BX, $0x756E6547 // "Genu"
JNE notintel
CMPL DX, $0x49656E69 // "ineI"
JNE notintel
CMPL CX, $0x6C65746E // "ntel"
JNE notintel
MOVB $1, runtime·isIntel(SB)
MOVB $1, runtime·lfenceBeforeRdtsc(SB)
notintel:
// Load EAX=1 cpuid flags
MOVL $1, AX
CPUID
MOVL CX, DI // Move to global variable clobbers CX when generating PIC
MOVL AX, runtime·processorVersionInfo(SB)
// Check for MMX support
TESTL $(1<<23), DX // MMX
JZ bad_proc
TESTL $(1<<26), DX // SSE2
SETNE runtime·support_sse2(SB)
TESTL $(1<<19), DI // SSE4.1
SETNE runtime·support_sse41(SB)
TESTL $(1<<23), DI // POPCNT
SETNE runtime·support_popcnt(SB)
TESTL $(1<<27), DI // OSXSAVE
SETNE runtime·support_osxsave(SB)
eax7:
// Load EAX=7/ECX=0 cpuid flags
CMPL SI, $7
JLT osavx
MOVL $7, AX
MOVL $0, CX
CPUID
// If OS support for XMM and YMM is not present
// support_avx2 will be set back to false later.
TESTL $(1<<5), BX
SETNE runtime·support_avx2(SB)
TESTL $(1<<9), BX // ERMS
SETNE runtime·support_erms(SB)
osavx:
// nacl does not support XGETBV to test
// for XMM and YMM OS support.
#ifndef GOOS_nacl
CMPB runtime·support_osxsave(SB), $1
JNE noavx
MOVL $0, CX
// For XGETBV, OSXSAVE bit is required and sufficient
XGETBV
ANDL $6, AX
CMPL AX, $6 // Check for OS support of XMM and YMM registers.
JE nocpuinfo
#endif
noavx:
MOVB $0, runtime·support_avx2(SB)
nocpuinfo:
// if there is an _cgo_init, call it to let it
// initialize and to set up GS. if not,
// we set up GS ourselves.
MOVL _cgo_init(SB), AX
TESTL AX, AX
JZ needtls
MOVL $setg_gcc<>(SB), BX
MOVL BX, 4(SP)
MOVL BP, 0(SP)
CALL AX
// update stackguard after _cgo_init
MOVL $runtime·g0(SB), CX
MOVL (g_stack+stack_lo)(CX), AX
ADDL $const__StackGuard, AX
MOVL AX, g_stackguard0(CX)
MOVL AX, g_stackguard1(CX)
#ifndef GOOS_windows
// skip runtime·ldt0setup(SB) and tls test after _cgo_init for non-windows
JMP ok
#endif
needtls:
#ifdef GOOS_plan9
// skip runtime·ldt0setup(SB) and tls test on Plan 9 in all cases
JMP ok
#endif
// set up %gs
CALL runtime·ldt0setup(SB)
// store through it, to make sure it works
get_tls(BX)
MOVL $0x123, g(BX)
MOVL runtime·m0+m_tls(SB), AX
CMPL AX, $0x123
JEQ ok
MOVL AX, 0 // abort
ok:
// set up m and g "registers"
get_tls(BX)
LEAL runtime·g0(SB), DX
MOVL DX, g(BX)
LEAL runtime·m0(SB), AX
// save m->g0 = g0
MOVL DX, m_g0(AX)
// save g0->m = m0
MOVL AX, g_m(DX)
CALL runtime·emptyfunc(SB) // fault if stack check is wrong
// convention is D is always cleared
CLD
CALL runtime·check(SB)
// saved argc, argv
MOVL 120(SP), AX
MOVL AX, 0(SP)
MOVL 124(SP), AX
MOVL AX, 4(SP)
CALL runtime·args(SB)
CALL runtime·osinit(SB)
CALL runtime·schedinit(SB)
// create a new goroutine to start program
PUSHL $runtime·mainPC(SB) // entry
PUSHL $0 // arg size
CALL runtime·newproc(SB)
POPL AX
POPL AX
// start this M
CALL runtime·mstart(SB)
CALL runtime·abort(SB)
RET
DATA bad_proc_msg<>+0x00(SB)/8, $"This pro"
DATA bad_proc_msg<>+0x08(SB)/8, $"gram can"
DATA bad_proc_msg<>+0x10(SB)/8, $" only be"
DATA bad_proc_msg<>+0x18(SB)/8, $" run on "
DATA bad_proc_msg<>+0x20(SB)/8, $"processo"
DATA bad_proc_msg<>+0x28(SB)/8, $"rs with "
DATA bad_proc_msg<>+0x30(SB)/8, $"MMX supp"
DATA bad_proc_msg<>+0x38(SB)/4, $"ort."
DATA bad_proc_msg<>+0x3c(SB)/1, $0xa
GLOBL bad_proc_msg<>(SB), RODATA, $0x3d
DATA runtime·mainPC+0(SB)/4,$runtime·main(SB)
GLOBL runtime·mainPC(SB),RODATA,$4
TEXT runtime·breakpoint(SB),NOSPLIT,$0-0
INT $3
RET
TEXT runtime·asminit(SB),NOSPLIT,$0-0
// Linux and MinGW start the FPU in extended double precision.
// Other operating systems use double precision.
// Change to double precision to match them,
// and to match other hardware that only has double.
FLDCW runtime·controlWord64(SB)
RET
/*
* go-routine
*/
// void gosave(Gobuf*)
// save state in Gobuf; setjmp
TEXT runtime·gosave(SB), NOSPLIT, $0-4
MOVL buf+0(FP), AX // gobuf
LEAL buf+0(FP), BX // caller's SP
MOVL BX, gobuf_sp(AX)
MOVL 0(SP), BX // caller's PC
MOVL BX, gobuf_pc(AX)
MOVL $0, gobuf_ret(AX)
// Assert ctxt is zero. See func save.
MOVL gobuf_ctxt(AX), BX
TESTL BX, BX
JZ 2(PC)
CALL runtime·badctxt(SB)
get_tls(CX)
MOVL g(CX), BX
MOVL BX, gobuf_g(AX)
RET
// void gogo(Gobuf*)
// restore state from Gobuf; longjmp
TEXT runtime·gogo(SB), NOSPLIT, $8-4
MOVL buf+0(FP), BX // gobuf
MOVL gobuf_g(BX), DX
MOVL 0(DX), CX // make sure g != nil
get_tls(CX)
MOVL DX, g(CX)
MOVL gobuf_sp(BX), SP // restore SP
MOVL gobuf_ret(BX), AX
MOVL gobuf_ctxt(BX), DX
MOVL $0, gobuf_sp(BX) // clear to help garbage collector
MOVL $0, gobuf_ret(BX)
MOVL $0, gobuf_ctxt(BX)
MOVL gobuf_pc(BX), BX
JMP BX
// func mcall(fn func(*g))
// Switch to m->g0's stack, call fn(g).
// Fn must never return. It should gogo(&g->sched)
// to keep running g.
TEXT runtime·mcall(SB), NOSPLIT, $0-4
MOVL fn+0(FP), DI
get_tls(DX)
MOVL g(DX), AX // save state in g->sched
MOVL 0(SP), BX // caller's PC
MOVL BX, (g_sched+gobuf_pc)(AX)
LEAL fn+0(FP), BX // caller's SP
MOVL BX, (g_sched+gobuf_sp)(AX)
MOVL AX, (g_sched+gobuf_g)(AX)
// switch to m->g0 & its stack, call fn
MOVL g(DX), BX
MOVL g_m(BX), BX
MOVL m_g0(BX), SI
CMPL SI, AX // if g == m->g0 call badmcall
JNE 3(PC)
MOVL $runtime·badmcall(SB), AX
JMP AX
MOVL SI, g(DX) // g = m->g0
MOVL (g_sched+gobuf_sp)(SI), SP // sp = m->g0->sched.sp
PUSHL AX
MOVL DI, DX
MOVL 0(DI), DI
CALL DI
POPL AX
MOVL $runtime·badmcall2(SB), AX
JMP AX
RET
// systemstack_switch is a dummy routine that systemstack leaves at the bottom
// of the G stack. We need to distinguish the routine that
// lives at the bottom of the G stack from the one that lives
// at the top of the system stack because the one at the top of
// the system stack terminates the stack walk (see topofstack()).
TEXT runtime·systemstack_switch(SB), NOSPLIT, $0-0
RET
// func systemstack(fn func())
TEXT runtime·systemstack(SB), NOSPLIT, $0-4
MOVL fn+0(FP), DI // DI = fn
get_tls(CX)
MOVL g(CX), AX // AX = g
MOVL g_m(AX), BX // BX = m
CMPL AX, m_gsignal(BX)
JEQ noswitch
MOVL m_g0(BX), DX // DX = g0
CMPL AX, DX
JEQ noswitch
CMPL AX, m_curg(BX)
JNE bad
// switch stacks
// save our state in g->sched. Pretend to
// be systemstack_switch if the G stack is scanned.
MOVL $runtime·systemstack_switch(SB), (g_sched+gobuf_pc)(AX)
MOVL SP, (g_sched+gobuf_sp)(AX)
MOVL AX, (g_sched+gobuf_g)(AX)
// switch to g0
get_tls(CX)
MOVL DX, g(CX)
MOVL (g_sched+gobuf_sp)(DX), BX
// make it look like mstart called systemstack on g0, to stop traceback
SUBL $4, BX
MOVL $runtime·mstart(SB), DX
MOVL DX, 0(BX)
MOVL BX, SP
// call target function
MOVL DI, DX
MOVL 0(DI), DI
CALL DI
// switch back to g
get_tls(CX)
MOVL g(CX), AX
MOVL g_m(AX), BX
MOVL m_curg(BX), AX
MOVL AX, g(CX)
MOVL (g_sched+gobuf_sp)(AX), SP
MOVL $0, (g_sched+gobuf_sp)(AX)
RET
noswitch:
// already on system stack; tail call the function
// Using a tail call here cleans up tracebacks since we won't stop
// at an intermediate systemstack.
MOVL DI, DX
MOVL 0(DI), DI
JMP DI
bad:
// Bad: g is not gsignal, not g0, not curg. What is it?
// Hide call from linker nosplit analysis.
MOVL $runtime·badsystemstack(SB), AX
CALL AX
INT $3
/*
* support for morestack
*/
// Called during function prolog when more stack is needed.
//
// The traceback routines see morestack on a g0 as being
// the top of a stack (for example, morestack calling newstack
// calling the scheduler calling newm calling gc), so we must
// record an argument size. For that purpose, it has no arguments.
TEXT runtime·morestack(SB),NOSPLIT,$0-0
// Cannot grow scheduler stack (m->g0).
get_tls(CX)
MOVL g(CX), BX
MOVL g_m(BX), BX
MOVL m_g0(BX), SI
CMPL g(CX), SI
JNE 3(PC)
CALL runtime·badmorestackg0(SB)
CALL runtime·abort(SB)
// Cannot grow signal stack.
MOVL m_gsignal(BX), SI
CMPL g(CX), SI
JNE 3(PC)
CALL runtime·badmorestackgsignal(SB)
CALL runtime·abort(SB)
// Called from f.
// Set m->morebuf to f's caller.
MOVL 4(SP), DI // f's caller's PC
MOVL DI, (m_morebuf+gobuf_pc)(BX)
LEAL 8(SP), CX // f's caller's SP
MOVL CX, (m_morebuf+gobuf_sp)(BX)
get_tls(CX)
MOVL g(CX), SI
MOVL SI, (m_morebuf+gobuf_g)(BX)
// Set g->sched to context in f.
MOVL 0(SP), AX // f's PC
MOVL AX, (g_sched+gobuf_pc)(SI)
MOVL SI, (g_sched+gobuf_g)(SI)
LEAL 4(SP), AX // f's SP
MOVL AX, (g_sched+gobuf_sp)(SI)
MOVL DX, (g_sched+gobuf_ctxt)(SI)
// Call newstack on m->g0's stack.
MOVL m_g0(BX), BP
MOVL BP, g(CX)
MOVL (g_sched+gobuf_sp)(BP), AX
MOVL -4(AX), BX // fault if CALL would, before smashing SP
MOVL AX, SP
CALL runtime·newstack(SB)
CALL runtime·abort(SB) // crash if newstack returns
RET
TEXT runtime·morestack_noctxt(SB),NOSPLIT,$0-0
MOVL $0, DX
JMP runtime·morestack(SB)
// reflectcall: call a function with the given argument list
// func call(argtype *_type, f *FuncVal, arg *byte, argsize, retoffset uint32).
// we don't have variable-sized frames, so we use a small number
// of constant-sized-frame functions to encode a few bits of size in the pc.
// Caution: ugly multiline assembly macros in your future!
#define DISPATCH(NAME,MAXSIZE) \
CMPL CX, $MAXSIZE; \
JA 3(PC); \
MOVL $NAME(SB), AX; \
JMP AX
// Note: can't just "JMP NAME(SB)" - bad inlining results.
TEXT reflect·call(SB), NOSPLIT, $0-0
JMP ·reflectcall(SB)
TEXT ·reflectcall(SB), NOSPLIT, $0-20
MOVL argsize+12(FP), CX
DISPATCH(runtime·call16, 16)
DISPATCH(runtime·call32, 32)
DISPATCH(runtime·call64, 64)
DISPATCH(runtime·call128, 128)
DISPATCH(runtime·call256, 256)
DISPATCH(runtime·call512, 512)
DISPATCH(runtime·call1024, 1024)
DISPATCH(runtime·call2048, 2048)
DISPATCH(runtime·call4096, 4096)
DISPATCH(runtime·call8192, 8192)
DISPATCH(runtime·call16384, 16384)
DISPATCH(runtime·call32768, 32768)
DISPATCH(runtime·call65536, 65536)
DISPATCH(runtime·call131072, 131072)
DISPATCH(runtime·call262144, 262144)
DISPATCH(runtime·call524288, 524288)
DISPATCH(runtime·call1048576, 1048576)
DISPATCH(runtime·call2097152, 2097152)
DISPATCH(runtime·call4194304, 4194304)
DISPATCH(runtime·call8388608, 8388608)
DISPATCH(runtime·call16777216, 16777216)
DISPATCH(runtime·call33554432, 33554432)
DISPATCH(runtime·call67108864, 67108864)
DISPATCH(runtime·call134217728, 134217728)
DISPATCH(runtime·call268435456, 268435456)
DISPATCH(runtime·call536870912, 536870912)
DISPATCH(runtime·call1073741824, 1073741824)
MOVL $runtime·badreflectcall(SB), AX
JMP AX
#define CALLFN(NAME,MAXSIZE) \
TEXT NAME(SB), WRAPPER, $MAXSIZE-20; \
NO_LOCAL_POINTERS; \
/* copy arguments to stack */ \
MOVL argptr+8(FP), SI; \
MOVL argsize+12(FP), CX; \
MOVL SP, DI; \
REP;MOVSB; \
/* call function */ \
MOVL f+4(FP), DX; \
MOVL (DX), AX; \
PCDATA $PCDATA_StackMapIndex, $0; \
CALL AX; \
/* copy return values back */ \
MOVL argtype+0(FP), DX; \
MOVL argptr+8(FP), DI; \
MOVL argsize+12(FP), CX; \
MOVL retoffset+16(FP), BX; \
MOVL SP, SI; \
ADDL BX, DI; \
ADDL BX, SI; \
SUBL BX, CX; \
CALL callRet<>(SB); \
RET
// callRet copies return values back at the end of call*. This is a
// separate function so it can allocate stack space for the arguments
// to reflectcallmove. It does not follow the Go ABI; it expects its
// arguments in registers.
TEXT callRet<>(SB), NOSPLIT, $16-0
MOVL DX, 0(SP)
MOVL DI, 4(SP)
MOVL SI, 8(SP)
MOVL CX, 12(SP)
CALL runtime·reflectcallmove(SB)
RET
CALLFN(·call16, 16)
CALLFN(·call32, 32)
CALLFN(·call64, 64)
CALLFN(·call128, 128)
CALLFN(·call256, 256)
CALLFN(·call512, 512)
CALLFN(·call1024, 1024)
CALLFN(·call2048, 2048)
CALLFN(·call4096, 4096)
CALLFN(·call8192, 8192)
CALLFN(·call16384, 16384)
CALLFN(·call32768, 32768)
CALLFN(·call65536, 65536)
CALLFN(·call131072, 131072)
CALLFN(·call262144, 262144)
CALLFN(·call524288, 524288)
CALLFN(·call1048576, 1048576)
CALLFN(·call2097152, 2097152)
CALLFN(·call4194304, 4194304)
CALLFN(·call8388608, 8388608)
CALLFN(·call16777216, 16777216)
CALLFN(·call33554432, 33554432)
CALLFN(·call67108864, 67108864)
CALLFN(·call134217728, 134217728)
CALLFN(·call268435456, 268435456)
CALLFN(·call536870912, 536870912)
CALLFN(·call1073741824, 1073741824)
TEXT runtime·procyield(SB),NOSPLIT,$0-0
MOVL cycles+0(FP), AX
again:
PAUSE
SUBL $1, AX
JNZ again
RET
TEXT ·publicationBarrier(SB),NOSPLIT,$0-0
// Stores are already ordered on x86, so this is just a
// compile barrier.
RET
// void jmpdefer(fn, sp);
// called from deferreturn.
// 1. pop the caller
// 2. sub 5 bytes (the length of CALL & a 32 bit displacement) from the callers
// return (when building for shared libraries, subtract 16 bytes -- 5 bytes
// for CALL & displacement to call __x86.get_pc_thunk.cx, 6 bytes for the
// LEAL to load the offset into BX, and finally 5 for the call & displacement)
// 3. jmp to the argument
TEXT runtime·jmpdefer(SB), NOSPLIT, $0-8
MOVL fv+0(FP), DX // fn
MOVL argp+4(FP), BX // caller sp
LEAL -4(BX), SP // caller sp after CALL
#ifdef GOBUILDMODE_shared
SUBL $16, (SP) // return to CALL again
#else
SUBL $5, (SP) // return to CALL again
#endif
MOVL 0(DX), BX
JMP BX // but first run the deferred function
// Save state of caller into g->sched.
TEXT gosave<>(SB),NOSPLIT,$0
PUSHL AX
PUSHL BX
get_tls(BX)
MOVL g(BX), BX
LEAL arg+0(FP), AX
MOVL AX, (g_sched+gobuf_sp)(BX)
MOVL -4(AX), AX
MOVL AX, (g_sched+gobuf_pc)(BX)
MOVL $0, (g_sched+gobuf_ret)(BX)
// Assert ctxt is zero. See func save.
MOVL (g_sched+gobuf_ctxt)(BX), AX
TESTL AX, AX
JZ 2(PC)
CALL runtime·badctxt(SB)
POPL BX
POPL AX
RET
// func asmcgocall(fn, arg unsafe.Pointer) int32
// Call fn(arg) on the scheduler stack,
// aligned appropriately for the gcc ABI.
// See cgocall.go for more details.
TEXT ·asmcgocall(SB),NOSPLIT,$0-12
MOVL fn+0(FP), AX
MOVL arg+4(FP), BX
MOVL SP, DX
// Figure out if we need to switch to m->g0 stack.
// We get called to create new OS threads too, and those
// come in on the m->g0 stack already.
get_tls(CX)
MOVL g(CX), BP
MOVL g_m(BP), BP
MOVL m_g0(BP), SI
MOVL g(CX), DI
CMPL SI, DI
JEQ noswitch
CALL gosave<>(SB)
get_tls(CX)
MOVL SI, g(CX)
MOVL (g_sched+gobuf_sp)(SI), SP
noswitch:
// Now on a scheduling stack (a pthread-created stack).
SUBL $32, SP
ANDL $~15, SP // alignment, perhaps unnecessary
MOVL DI, 8(SP) // save g
MOVL (g_stack+stack_hi)(DI), DI
SUBL DX, DI
MOVL DI, 4(SP) // save depth in stack (can't just save SP, as stack might be copied during a callback)
MOVL BX, 0(SP) // first argument in x86-32 ABI
CALL AX
// Restore registers, g, stack pointer.
get_tls(CX)
MOVL 8(SP), DI
MOVL (g_stack+stack_hi)(DI), SI
SUBL 4(SP), SI
MOVL DI, g(CX)
MOVL SI, SP
MOVL AX, ret+8(FP)
RET
// cgocallback(void (*fn)(void*), void *frame, uintptr framesize, uintptr ctxt)
// Turn the fn into a Go func (by taking its address) and call
// cgocallback_gofunc.
TEXT runtime·cgocallback(SB),NOSPLIT,$16-16
LEAL fn+0(FP), AX
MOVL AX, 0(SP)
MOVL frame+4(FP), AX
MOVL AX, 4(SP)
MOVL framesize+8(FP), AX
MOVL AX, 8(SP)
MOVL ctxt+12(FP), AX
MOVL AX, 12(SP)
MOVL $runtime·cgocallback_gofunc(SB), AX
CALL AX
RET
// cgocallback_gofunc(FuncVal*, void *frame, uintptr framesize, uintptr ctxt)
// See cgocall.go for more details.
TEXT ·cgocallback_gofunc(SB),NOSPLIT,$12-16
NO_LOCAL_POINTERS
// If g is nil, Go did not create the current thread.
// Call needm to obtain one for temporary use.
// In this case, we're running on the thread stack, so there's
// lots of space, but the linker doesn't know. Hide the call from
// the linker analysis by using an indirect call through AX.
get_tls(CX)
#ifdef GOOS_windows
MOVL $0, BP
CMPL CX, $0
JEQ 2(PC) // TODO
#endif
MOVL g(CX), BP
CMPL BP, $0
JEQ needm
MOVL g_m(BP), BP
MOVL BP, DX // saved copy of oldm
JMP havem
needm:
MOVL $0, 0(SP)
MOVL $runtime·needm(SB), AX
CALL AX
MOVL 0(SP), DX
get_tls(CX)
MOVL g(CX), BP
MOVL g_m(BP), BP
// Set m->sched.sp = SP, so that if a panic happens
// during the function we are about to execute, it will
// have a valid SP to run on the g0 stack.
// The next few lines (after the havem label)
// will save this SP onto the stack and then write
// the same SP back to m->sched.sp. That seems redundant,
// but if an unrecovered panic happens, unwindm will
// restore the g->sched.sp from the stack location
// and then systemstack will try to use it. If we don't set it here,
// that restored SP will be uninitialized (typically 0) and
// will not be usable.
MOVL m_g0(BP), SI
MOVL SP, (g_sched+gobuf_sp)(SI)
havem:
// Now there's a valid m, and we're running on its m->g0.
// Save current m->g0->sched.sp on stack and then set it to SP.
// Save current sp in m->g0->sched.sp in preparation for
// switch back to m->curg stack.
// NOTE: unwindm knows that the saved g->sched.sp is at 0(SP).
MOVL m_g0(BP), SI
MOVL (g_sched+gobuf_sp)(SI), AX
MOVL AX, 0(SP)
MOVL SP, (g_sched+gobuf_sp)(SI)
// Switch to m->curg stack and call runtime.cgocallbackg.
// Because we are taking over the execution of m->curg
// but *not* resuming what had been running, we need to
// save that information (m->curg->sched) so we can restore it.
// We can restore m->curg->sched.sp easily, because calling
// runtime.cgocallbackg leaves SP unchanged upon return.
// To save m->curg->sched.pc, we push it onto the stack.
// This has the added benefit that it looks to the traceback
// routine like cgocallbackg is going to return to that
// PC (because the frame we allocate below has the same
// size as cgocallback_gofunc's frame declared above)
// so that the traceback will seamlessly trace back into
// the earlier calls.
//
// In the new goroutine, 4(SP) holds the saved oldm (DX) register.
// 8(SP) is unused.
MOVL m_curg(BP), SI
MOVL SI, g(CX)
MOVL (g_sched+gobuf_sp)(SI), DI // prepare stack as DI
MOVL (g_sched+gobuf_pc)(SI), BP
MOVL BP, -4(DI)
MOVL ctxt+12(FP), CX
LEAL -(4+12)(DI), SP
MOVL DX, 4(SP)
MOVL CX, 0(SP)
CALL runtime·cgocallbackg(SB)
MOVL 4(SP), DX
// Restore g->sched (== m->curg->sched) from saved values.
get_tls(CX)
MOVL g(CX), SI
MOVL 12(SP), BP
MOVL BP, (g_sched+gobuf_pc)(SI)
LEAL (12+4)(SP), DI
MOVL DI, (g_sched+gobuf_sp)(SI)
// Switch back to m->g0's stack and restore m->g0->sched.sp.
// (Unlike m->curg, the g0 goroutine never uses sched.pc,
// so we do not have to restore it.)
MOVL g(CX), BP
MOVL g_m(BP), BP
MOVL m_g0(BP), SI
MOVL SI, g(CX)
MOVL (g_sched+gobuf_sp)(SI), SP
MOVL 0(SP), AX
MOVL AX, (g_sched+gobuf_sp)(SI)
// If the m on entry was nil, we called needm above to borrow an m
// for the duration of the call. Since the call is over, return it with dropm.
CMPL DX, $0
JNE 3(PC)
MOVL $runtime·dropm(SB), AX
CALL AX
// Done!
RET
// void setg(G*); set g. for use by needm.
TEXT runtime·setg(SB), NOSPLIT, $0-4
MOVL gg+0(FP), BX
#ifdef GOOS_windows
CMPL BX, $0
JNE settls
MOVL $0, 0x14(FS)
RET
settls:
MOVL g_m(BX), AX
LEAL m_tls(AX), AX
MOVL AX, 0x14(FS)
#endif
get_tls(CX)
MOVL BX, g(CX)
RET
// void setg_gcc(G*); set g. for use by gcc
TEXT setg_gcc<>(SB), NOSPLIT, $0
get_tls(AX)
MOVL gg+0(FP), DX
MOVL DX, g(AX)
RET
TEXT runtime·abort(SB),NOSPLIT,$0-0
INT $3
loop:
JMP loop
// check that SP is in range [g->stack.lo, g->stack.hi)
TEXT runtime·stackcheck(SB), NOSPLIT, $0-0
get_tls(CX)
MOVL g(CX), AX
CMPL (g_stack+stack_hi)(AX), SP
JHI 2(PC)
CALL runtime·abort(SB)
CMPL SP, (g_stack+stack_lo)(AX)
JHI 2(PC)
CALL runtime·abort(SB)
RET
// func cputicks() int64
TEXT runtime·cputicks(SB),NOSPLIT,$0-8
CMPB runtime·support_sse2(SB), $1
JNE done
CMPB runtime·lfenceBeforeRdtsc(SB), $1
JNE mfence
LFENCE
JMP done
mfence:
MFENCE
done:
RDTSC
MOVL AX, ret_lo+0(FP)
MOVL DX, ret_hi+4(FP)
RET
TEXT runtime·ldt0setup(SB),NOSPLIT,$16-0
// set up ldt 7 to point at m0.tls
// ldt 1 would be fine on Linux, but on OS X, 7 is as low as we can go.
// the entry number is just a hint. setldt will set up GS with what it used.
MOVL $7, 0(SP)
LEAL runtime·m0+m_tls(SB), AX
MOVL AX, 4(SP)
MOVL $32, 8(SP) // sizeof(tls array)
CALL runtime·setldt(SB)
RET
TEXT runtime·emptyfunc(SB),0,$0-0
RET
// hash function using AES hardware instructions
TEXT runtime·aeshash(SB),NOSPLIT,$0-16
MOVL p+0(FP), AX // ptr to data
MOVL s+8(FP), BX // size
LEAL ret+12(FP), DX
JMP runtime·aeshashbody(SB)
TEXT runtime·aeshashstr(SB),NOSPLIT,$0-12
MOVL p+0(FP), AX // ptr to string object
MOVL 4(AX), BX // length of string
MOVL (AX), AX // string data
LEAL ret+8(FP), DX
JMP runtime·aeshashbody(SB)
// AX: data
// BX: length
// DX: address to put return value
TEXT runtime·aeshashbody(SB),NOSPLIT,$0-0
MOVL h+4(FP), X0 // 32 bits of per-table hash seed
PINSRW $4, BX, X0 // 16 bits of length
PSHUFHW $0, X0, X0 // replace size with its low 2 bytes repeated 4 times
MOVO X0, X1 // save unscrambled seed
PXOR runtime·aeskeysched(SB), X0 // xor in per-process seed
AESENC X0, X0 // scramble seed
CMPL BX, $16
JB aes0to15
JE aes16
CMPL BX, $32
JBE aes17to32
CMPL BX, $64
JBE aes33to64
JMP aes65plus
aes0to15:
TESTL BX, BX
JE aes0
ADDL $16, AX
TESTW $0xff0, AX
JE endofpage
// 16 bytes loaded at this address won't cross
// a page boundary, so we can load it directly.
MOVOU -16(AX), X1
ADDL BX, BX
PAND masks<>(SB)(BX*8), X1
final1:
AESENC X0, X1 // scramble input, xor in seed
AESENC X1, X1 // scramble combo 2 times
AESENC X1, X1
MOVL X1, (DX)
RET
endofpage:
// address ends in 1111xxxx. Might be up against
// a page boundary, so load ending at last byte.
// Then shift bytes down using pshufb.
MOVOU -32(AX)(BX*1), X1
ADDL BX, BX
PSHUFB shifts<>(SB)(BX*8), X1
JMP final1
aes0:
// Return scrambled input seed
AESENC X0, X0
MOVL X0, (DX)
RET
aes16:
MOVOU (AX), X1
JMP final1
aes17to32:
// make second starting seed
PXOR runtime·aeskeysched+16(SB), X1
AESENC X1, X1
// load data to be hashed
MOVOU (AX), X2
MOVOU -16(AX)(BX*1), X3
// scramble 3 times
AESENC X0, X2
AESENC X1, X3
AESENC X2, X2
AESENC X3, X3
AESENC X2, X2
AESENC X3, X3
// combine results
PXOR X3, X2
MOVL X2, (DX)
RET
aes33to64:
// make 3 more starting seeds
MOVO X1, X2
MOVO X1, X3
PXOR runtime·aeskeysched+16(SB), X1
PXOR runtime·aeskeysched+32(SB), X2
PXOR runtime·aeskeysched+48(SB), X3
AESENC X1, X1
AESENC X2, X2
AESENC X3, X3
MOVOU (AX), X4
MOVOU 16(AX), X5
MOVOU -32(AX)(BX*1), X6
MOVOU -16(AX)(BX*1), X7
AESENC X0, X4
AESENC X1, X5
AESENC X2, X6
AESENC X3, X7
AESENC X4, X4
AESENC X5, X5
AESENC X6, X6
AESENC X7, X7
AESENC X4, X4
AESENC X5, X5
AESENC X6, X6
AESENC X7, X7
PXOR X6, X4
PXOR X7, X5
PXOR X5, X4
MOVL X4, (DX)
RET
aes65plus:
// make 3 more starting seeds
MOVO X1, X2
MOVO X1, X3
PXOR runtime·aeskeysched+16(SB), X1
PXOR runtime·aeskeysched+32(SB), X2
PXOR runtime·aeskeysched+48(SB), X3
AESENC X1, X1
AESENC X2, X2
AESENC X3, X3
// start with last (possibly overlapping) block
MOVOU -64(AX)(BX*1), X4
MOVOU -48(AX)(BX*1), X5
MOVOU -32(AX)(BX*1), X6
MOVOU -16(AX)(BX*1), X7
// scramble state once
AESENC X0, X4
AESENC X1, X5
AESENC X2, X6
AESENC X3, X7
// compute number of remaining 64-byte blocks
DECL BX
SHRL $6, BX
aesloop:
// scramble state, xor in a block
MOVOU (AX), X0
MOVOU 16(AX), X1
MOVOU 32(AX), X2
MOVOU 48(AX), X3
AESENC X0, X4
AESENC X1, X5
AESENC X2, X6
AESENC X3, X7
// scramble state
AESENC X4, X4
AESENC X5, X5
AESENC X6, X6
AESENC X7, X7
ADDL $64, AX
DECL BX
JNE aesloop
// 2 more scrambles to finish
AESENC X4, X4
AESENC X5, X5
AESENC X6, X6
AESENC X7, X7
AESENC X4, X4
AESENC X5, X5
AESENC X6, X6
AESENC X7, X7
PXOR X6, X4
PXOR X7, X5
PXOR X5, X4
MOVL X4, (DX)
RET
TEXT runtime·aeshash32(SB),NOSPLIT,$0-12
MOVL p+0(FP), AX // ptr to data
MOVL h+4(FP), X0 // seed
PINSRD $1, (AX), X0 // data
AESENC runtime·aeskeysched+0(SB), X0
AESENC runtime·aeskeysched+16(SB), X0
AESENC runtime·aeskeysched+32(SB), X0
MOVL X0, ret+8(FP)
RET
TEXT runtime·aeshash64(SB),NOSPLIT,$0-12
MOVL p+0(FP), AX // ptr to data
MOVQ (AX), X0 // data
PINSRD $2, h+4(FP), X0 // seed
AESENC runtime·aeskeysched+0(SB), X0
AESENC runtime·aeskeysched+16(SB), X0
AESENC runtime·aeskeysched+32(SB), X0
MOVL X0, ret+8(FP)
RET
// simple mask to get rid of data in the high part of the register.
DATA masks<>+0x00(SB)/4, $0x00000000
DATA masks<>+0x04(SB)/4, $0x00000000
DATA masks<>+0x08(SB)/4, $0x00000000
DATA masks<>+0x0c(SB)/4, $0x00000000
DATA masks<>+0x10(SB)/4, $0x000000ff
DATA masks<>+0x14(SB)/4, $0x00000000
DATA masks<>+0x18(SB)/4, $0x00000000
DATA masks<>+0x1c(SB)/4, $0x00000000
DATA masks<>+0x20(SB)/4, $0x0000ffff
DATA masks<>+0x24(SB)/4, $0x00000000
DATA masks<>+0x28(SB)/4, $0x00000000
DATA masks<>+0x2c(SB)/4, $0x00000000
DATA masks<>+0x30(SB)/4, $0x00ffffff
DATA masks<>+0x34(SB)/4, $0x00000000
DATA masks<>+0x38(SB)/4, $0x00000000
DATA masks<>+0x3c(SB)/4, $0x00000000
DATA masks<>+0x40(SB)/4, $0xffffffff
DATA masks<>+0x44(SB)/4, $0x00000000
DATA masks<>+0x48(SB)/4, $0x00000000
DATA masks<>+0x4c(SB)/4, $0x00000000
DATA masks<>+0x50(SB)/4, $0xffffffff
DATA masks<>+0x54(SB)/4, $0x000000ff
DATA masks<>+0x58(SB)/4, $0x00000000
DATA masks<>+0x5c(SB)/4, $0x00000000
DATA masks<>+0x60(SB)/4, $0xffffffff
DATA masks<>+0x64(SB)/4, $0x0000ffff
DATA masks<>+0x68(SB)/4, $0x00000000
DATA masks<>+0x6c(SB)/4, $0x00000000
DATA masks<>+0x70(SB)/4, $0xffffffff
DATA masks<>+0x74(SB)/4, $0x00ffffff
DATA masks<>+0x78(SB)/4, $0x00000000
DATA masks<>+0x7c(SB)/4, $0x00000000
DATA masks<>+0x80(SB)/4, $0xffffffff
DATA masks<>+0x84(SB)/4, $0xffffffff
DATA masks<>+0x88(SB)/4, $0x00000000
DATA masks<>+0x8c(SB)/4, $0x00000000
DATA masks<>+0x90(SB)/4, $0xffffffff
DATA masks<>+0x94(SB)/4, $0xffffffff
DATA masks<>+0x98(SB)/4, $0x000000ff
DATA masks<>+0x9c(SB)/4, $0x00000000
DATA masks<>+0xa0(SB)/4, $0xffffffff
DATA masks<>+0xa4(SB)/4, $0xffffffff
DATA masks<>+0xa8(SB)/4, $0x0000ffff
DATA masks<>+0xac(SB)/4, $0x00000000
DATA masks<>+0xb0(SB)/4, $0xffffffff
DATA masks<>+0xb4(SB)/4, $0xffffffff
DATA masks<>+0xb8(SB)/4, $0x00ffffff
DATA masks<>+0xbc(SB)/4, $0x00000000
DATA masks<>+0xc0(SB)/4, $0xffffffff
DATA masks<>+0xc4(SB)/4, $0xffffffff
DATA masks<>+0xc8(SB)/4, $0xffffffff
DATA masks<>+0xcc(SB)/4, $0x00000000
DATA masks<>+0xd0(SB)/4, $0xffffffff
DATA masks<>+0xd4(SB)/4, $0xffffffff
DATA masks<>+0xd8(SB)/4, $0xffffffff
DATA masks<>+0xdc(SB)/4, $0x000000ff
DATA masks<>+0xe0(SB)/4, $0xffffffff
DATA masks<>+0xe4(SB)/4, $0xffffffff
DATA masks<>+0xe8(SB)/4, $0xffffffff
DATA masks<>+0xec(SB)/4, $0x0000ffff
DATA masks<>+0xf0(SB)/4, $0xffffffff
DATA masks<>+0xf4(SB)/4, $0xffffffff
DATA masks<>+0xf8(SB)/4, $0xffffffff
DATA masks<>+0xfc(SB)/4, $0x00ffffff
GLOBL masks<>(SB),RODATA,$256
// these are arguments to pshufb. They move data down from
// the high bytes of the register to the low bytes of the register.
// index is how many bytes to move.
DATA shifts<>+0x00(SB)/4, $0x00000000
DATA shifts<>+0x04(SB)/4, $0x00000000
DATA shifts<>+0x08(SB)/4, $0x00000000
DATA shifts<>+0x0c(SB)/4, $0x00000000
DATA shifts<>+0x10(SB)/4, $0xffffff0f
DATA shifts<>+0x14(SB)/4, $0xffffffff
DATA shifts<>+0x18(SB)/4, $0xffffffff
DATA shifts<>+0x1c(SB)/4, $0xffffffff
DATA shifts<>+0x20(SB)/4, $0xffff0f0e
DATA shifts<>+0x24(SB)/4, $0xffffffff
DATA shifts<>+0x28(SB)/4, $0xffffffff
DATA shifts<>+0x2c(SB)/4, $0xffffffff
DATA shifts<>+0x30(SB)/4, $0xff0f0e0d
DATA shifts<>+0x34(SB)/4, $0xffffffff
DATA shifts<>+0x38(SB)/4, $0xffffffff
DATA shifts<>+0x3c(SB)/4, $0xffffffff
DATA shifts<>+0x40(SB)/4, $0x0f0e0d0c
DATA shifts<>+0x44(SB)/4, $0xffffffff
DATA shifts<>+0x48(SB)/4, $0xffffffff
DATA shifts<>+0x4c(SB)/4, $0xffffffff
DATA shifts<>+0x50(SB)/4, $0x0e0d0c0b
DATA shifts<>+0x54(SB)/4, $0xffffff0f
DATA shifts<>+0x58(SB)/4, $0xffffffff
DATA shifts<>+0x5c(SB)/4, $0xffffffff
DATA shifts<>+0x60(SB)/4, $0x0d0c0b0a
DATA shifts<>+0x64(SB)/4, $0xffff0f0e
DATA shifts<>+0x68(SB)/4, $0xffffffff
DATA shifts<>+0x6c(SB)/4, $0xffffffff
DATA shifts<>+0x70(SB)/4, $0x0c0b0a09
DATA shifts<>+0x74(SB)/4, $0xff0f0e0d
DATA shifts<>+0x78(SB)/4, $0xffffffff
DATA shifts<>+0x7c(SB)/4, $0xffffffff
DATA shifts<>+0x80(SB)/4, $0x0b0a0908
DATA shifts<>+0x84(SB)/4, $0x0f0e0d0c
DATA shifts<>+0x88(SB)/4, $0xffffffff
DATA shifts<>+0x8c(SB)/4, $0xffffffff
DATA shifts<>+0x90(SB)/4, $0x0a090807
DATA shifts<>+0x94(SB)/4, $0x0e0d0c0b
DATA shifts<>+0x98(SB)/4, $0xffffff0f
DATA shifts<>+0x9c(SB)/4, $0xffffffff
DATA shifts<>+0xa0(SB)/4, $0x09080706
DATA shifts<>+0xa4(SB)/4, $0x0d0c0b0a
DATA shifts<>+0xa8(SB)/4, $0xffff0f0e
DATA shifts<>+0xac(SB)/4, $0xffffffff
DATA shifts<>+0xb0(SB)/4, $0x08070605
DATA shifts<>+0xb4(SB)/4, $0x0c0b0a09
DATA shifts<>+0xb8(SB)/4, $0xff0f0e0d
DATA shifts<>+0xbc(SB)/4, $0xffffffff
DATA shifts<>+0xc0(SB)/4, $0x07060504
DATA shifts<>+0xc4(SB)/4, $0x0b0a0908
DATA shifts<>+0xc8(SB)/4, $0x0f0e0d0c
DATA shifts<>+0xcc(SB)/4, $0xffffffff
DATA shifts<>+0xd0(SB)/4, $0x06050403
DATA shifts<>+0xd4(SB)/4, $0x0a090807
DATA shifts<>+0xd8(SB)/4, $0x0e0d0c0b
DATA shifts<>+0xdc(SB)/4, $0xffffff0f
DATA shifts<>+0xe0(SB)/4, $0x05040302
DATA shifts<>+0xe4(SB)/4, $0x09080706
DATA shifts<>+0xe8(SB)/4, $0x0d0c0b0a
DATA shifts<>+0xec(SB)/4, $0xffff0f0e
DATA shifts<>+0xf0(SB)/4, $0x04030201
DATA shifts<>+0xf4(SB)/4, $0x08070605
DATA shifts<>+0xf8(SB)/4, $0x0c0b0a09
DATA shifts<>+0xfc(SB)/4, $0xff0f0e0d
GLOBL shifts<>(SB),RODATA,$256
TEXT ·checkASM(SB),NOSPLIT,$0-1
// check that masks<>(SB) and shifts<>(SB) are aligned to 16-byte
MOVL $masks<>(SB), AX
MOVL $shifts<>(SB), BX
ORL BX, AX
TESTL $15, AX
SETEQ ret+0(FP)
RET
TEXT runtime·return0(SB), NOSPLIT, $0
MOVL $0, AX
RET
// Called from cgo wrappers, this function returns g->m->curg.stack.hi.
// Must obey the gcc calling convention.
TEXT _cgo_topofstack(SB),NOSPLIT,$0
get_tls(CX)
MOVL g(CX), AX
MOVL g_m(AX), AX
MOVL m_curg(AX), AX
MOVL (g_stack+stack_hi)(AX), AX
RET
// The top-most function running on a goroutine
// returns to goexit+PCQuantum.
TEXT runtime·goexit(SB),NOSPLIT,$0-0
BYTE $0x90 // NOP
CALL runtime·goexit1(SB) // does not return
// traceback from goexit1 must hit code range of goexit
BYTE $0x90 // NOP
// Add a module's moduledata to the linked list of moduledata objects. This
// is called from .init_array by a function generated in the linker and so
// follows the platform ABI wrt register preservation -- it only touches AX,
// CX (implicitly) and DX, but it does not follow the ABI wrt arguments:
// instead the pointer to the moduledata is passed in AX.
TEXT runtime·addmoduledata(SB),NOSPLIT,$0-0
MOVL runtime·lastmoduledatap(SB), DX
MOVL AX, moduledata_next(DX)
MOVL AX, runtime·lastmoduledatap(SB)
RET
TEXT runtime·uint32tofloat64(SB),NOSPLIT,$8-12
MOVL a+0(FP), AX
MOVL AX, 0(SP)
MOVL $0, 4(SP)
FMOVV 0(SP), F0
FMOVDP F0, ret+4(FP)
RET
TEXT runtime·float64touint32(SB),NOSPLIT,$12-12
FMOVD a+0(FP), F0
FSTCW 0(SP)
FLDCW runtime·controlWord64trunc(SB)
FMOVVP F0, 4(SP)
FLDCW 0(SP)
MOVL 4(SP), AX
MOVL AX, ret+8(FP)
RET
// gcWriteBarrier performs a heap pointer write and informs the GC.
//
// gcWriteBarrier does NOT follow the Go ABI. It takes two arguments:
// - DI is the destination of the write
// - AX is the value being written at DI
// It clobbers FLAGS. It does not clobber any general-purpose registers,
// but may clobber others (e.g., SSE registers).
TEXT runtime·gcWriteBarrier(SB),NOSPLIT,$28
// Save the registers clobbered by the fast path. This is slightly
// faster than having the caller spill these.
MOVL CX, 20(SP)
MOVL BX, 24(SP)
// TODO: Consider passing g.m.p in as an argument so they can be shared
// across a sequence of write barriers.
get_tls(BX)
MOVL g(BX), BX
MOVL g_m(BX), BX
MOVL m_p(BX), BX
MOVL (p_wbBuf+wbBuf_next)(BX), CX
// Increment wbBuf.next position.
LEAL 8(CX), CX
MOVL CX, (p_wbBuf+wbBuf_next)(BX)
CMPL CX, (p_wbBuf+wbBuf_end)(BX)
// Record the write.
MOVL AX, -8(CX) // Record value
MOVL (DI), BX // TODO: This turns bad writes into bad reads.
MOVL BX, -4(CX) // Record *slot
// Is the buffer full? (flags set in CMPL above)
JEQ flush
ret:
MOVL 20(SP), CX
MOVL 24(SP), BX
// Do the write.
MOVL AX, (DI)
RET
flush:
// Save all general purpose registers since these could be
// clobbered by wbBufFlush and were not saved by the caller.
MOVL DI, 0(SP) // Also first argument to wbBufFlush
MOVL AX, 4(SP) // Also second argument to wbBufFlush
// BX already saved
// CX already saved
MOVL DX, 8(SP)
MOVL BP, 12(SP)
MOVL SI, 16(SP)
// DI already saved
// This takes arguments DI and AX
CALL runtime·wbBufFlush(SB)
MOVL 0(SP), DI
MOVL 4(SP), AX
MOVL 8(SP), DX
MOVL 12(SP), BP
MOVL 16(SP), SI
JMP ret
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