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asm_386.s
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asm_386.s
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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|NOFRAME|TOPFRAME,$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
// 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
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
CMPL BX, $0x756E6547 // "Genu"
JNE notintel
CMPL DX, $0x49656E69 // "ineI"
JNE notintel
CMPL CX, $0x6C65746E // "ntel"
JNE notintel
MOVB $1, runtime·isIntel(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
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
#ifdef GOOS_android
// arg 4: TLS base, stored in slot 0 (Android's TLS_SLOT_SELF).
// Compensate for tls_g (+8).
MOVL -8(TLS), BX
MOVL BX, 12(SP)
MOVL $runtime·tls_g(SB), 8(SP) // arg 3: &tls_g
#else
MOVL $0, BX
MOVL BX, 12(SP) // arg 3,4: not used when using platform's TLS
MOVL BX, 8(SP)
#endif
MOVL $setg_gcc<>(SB), BX
MOVL BX, 4(SP) // arg 2: setg_gcc
MOVL BP, 0(SP) // arg 1: g0
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_openbsd
// skip runtime·ldt0setup(SB) and tls test on OpenBSD in all cases
JMP ok
#endif
#ifdef GOOS_plan9
// skip runtime·ldt0setup(SB) and tls test on Plan 9 in all cases
JMP ok
#endif
// set up %gs
CALL 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
CALL runtime·newproc(SB)
POPL AX
// start this M
CALL runtime·mstart(SB)
CALL runtime·abort(SB)
RET
DATA bad_proc_msg<>+0x00(SB)/61, $"This program can only be run on processors with MMX support.\n"
GLOBL bad_proc_msg<>(SB), RODATA, $61
DATA runtime·mainPC+0(SB)/4,$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
TEXT runtime·mstart(SB),NOSPLIT|TOPFRAME,$0
CALL runtime·mstart0(SB)
RET // not reached
/*
* go-routine
*/
// void gogo(Gobuf*)
// restore state from Gobuf; longjmp
TEXT runtime·gogo(SB), NOSPLIT, $0-4
MOVL buf+0(FP), BX // gobuf
MOVL gobuf_g(BX), DX
MOVL 0(DX), CX // make sure g != nil
JMP gogo<>(SB)
TEXT gogo<>(SB), NOSPLIT, $0
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)
// 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.
CALL gosave_systemstack_switch<>(SB)
// switch to g0
get_tls(CX)
MOVL DX, g(CX)
MOVL (g_sched+gobuf_sp)(DX), 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.
NOP SP // tell vet SP changed - stop checking offsets
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)
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(stackArgsType *_type, f *FuncVal, stackArgs *byte, stackArgsSize, stackRetOffset, frameSize uint32, regArgs *abi.RegArgs).
// 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 ·reflectcall(SB), NOSPLIT, $0-28
MOVL frameSize+20(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-28; \
NO_LOCAL_POINTERS; \
/* copy arguments to stack */ \
MOVL stackArgs+8(FP), SI; \
MOVL stackArgsSize+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 stackArgsType+0(FP), DX; \
MOVL stackArgs+8(FP), DI; \
MOVL stackArgsSize+12(FP), CX; \
MOVL stackRetOffset+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, $20-0
MOVL DX, 0(SP)
MOVL DI, 4(SP)
MOVL SI, 8(SP)
MOVL CX, 12(SP)
MOVL $0, 16(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
// Save state of caller into g->sched,
// but using fake PC from systemstack_switch.
// Must only be called from functions with no locals ($0)
// or else unwinding from systemstack_switch is incorrect.
TEXT gosave_systemstack_switch<>(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 $runtime·systemstack_switch(SB), 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·abort(SB)
POPL BX
POPL AX
RET
// func asmcgocall_no_g(fn, arg unsafe.Pointer)
// Call fn(arg) aligned appropriately for the gcc ABI.
// Called on a system stack, and there may be no g yet (during needm).
TEXT ·asmcgocall_no_g(SB),NOSPLIT,$0-8
MOVL fn+0(FP), AX
MOVL arg+4(FP), BX
MOVL SP, DX
SUBL $32, SP
ANDL $~15, SP // alignment, perhaps unnecessary
MOVL DX, 8(SP) // save old SP
MOVL BX, 0(SP) // first argument in x86-32 ABI
CALL AX
MOVL 8(SP), DX
MOVL DX, SP
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. Or we might already
// be on the m->gsignal stack.
get_tls(CX)
MOVL g(CX), DI
CMPL DI, $0
JEQ nosave // Don't even have a G yet.
MOVL g_m(DI), BP
CMPL DI, m_gsignal(BP)
JEQ noswitch
MOVL m_g0(BP), SI
CMPL DI, SI
JEQ noswitch
CALL gosave_systemstack_switch<>(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
nosave:
// Now on a scheduling stack (a pthread-created stack).
SUBL $32, SP
ANDL $~15, SP // alignment, perhaps unnecessary
MOVL DX, 4(SP) // save original stack pointer
MOVL BX, 0(SP) // first argument in x86-32 ABI
CALL AX
MOVL 4(SP), CX // restore original stack pointer
MOVL CX, SP
MOVL AX, ret+8(FP)
RET
// cgocallback(fn, frame unsafe.Pointer, ctxt uintptr)
// See cgocall.go for more details.
TEXT ·cgocallback(SB),NOSPLIT,$12-12 // Frame size must match commented places below
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, savedm-4(SP) // saved copy of oldm
JMP havem
needm:
MOVL $runtime·needm(SB), AX
CALL AX
MOVL $0, savedm-4(SP) // dropm on return
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 curg stack and
// open a frame the same size as cgocallback's g0 frame.
// Once we switch to the curg stack, the pushed PC will appear
// to be the return PC of cgocallback, so that the traceback
// will seamlessly trace back into the earlier calls.
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) // "push" return PC on the g stack
// Gather our arguments into registers.
MOVL fn+0(FP), AX
MOVL frame+4(FP), BX
MOVL ctxt+8(FP), CX
LEAL -(4+12)(DI), SP // Must match declared frame size
MOVL AX, 0(SP)
MOVL BX, 4(SP)
MOVL CX, 8(SP)
CALL runtime·cgocallbackg(SB)
// Restore g->sched (== m->curg->sched) from saved values.
get_tls(CX)
MOVL g(CX), SI
MOVL 12(SP), BP // Must match declared frame size
MOVL BP, (g_sched+gobuf_pc)(SI)
LEAL (12+4)(SP), DI // Must match declared frame size
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.
MOVL savedm-4(SP), DX
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
// LFENCE/MFENCE instruction support is dependent on SSE2.
// When no SSE2 support is present do not enforce any serialization
// since using CPUID to serialize the instruction stream is
// very costly.
#ifdef GO386_softfloat
JMP rdtsc // no fence instructions available
#endif
CMPB internal∕cpu·X86+const_offsetX86HasRDTSCP(SB), $1
JNE fences
// Instruction stream serializing RDTSCP is supported.
// RDTSCP is supported by Intel Nehalem (2008) and
// AMD K8 Rev. F (2006) and newer.
RDTSCP
done:
MOVL AX, ret_lo+0(FP)
MOVL DX, ret_hi+4(FP)
RET
fences:
// MFENCE is instruction stream serializing and flushes the
// store buffers on AMD. The serialization semantics of LFENCE on AMD
// are dependent on MSR C001_1029 and CPU generation.
// LFENCE on Intel does wait for all previous instructions to have executed.
// Intel recommends MFENCE;LFENCE in its manuals before RDTSC to have all
// previous instructions executed and all previous loads and stores to globally visible.
// Using MFENCE;LFENCE here aligns the serializing properties without
// runtime detection of CPU manufacturer.
MFENCE
LFENCE
rdtsc:
RDTSC
JMP done
TEXT 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·memhash(SB),NOSPLIT,$0-16
CMPB runtime·useAeshash(SB), $0
JEQ noaes
MOVL p+0(FP), AX // ptr to data
MOVL s+8(FP), BX // size
LEAL ret+12(FP), DX
JMP aeshashbody<>(SB)
noaes:
JMP runtime·memhashFallback(SB)
TEXT runtime·strhash(SB),NOSPLIT,$0-12
CMPB runtime·useAeshash(SB), $0
JEQ noaes
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 aeshashbody<>(SB)
noaes:
JMP runtime·strhashFallback(SB)
// AX: data
// BX: length
// DX: address to put return value
TEXT 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