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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 "386/asm.h"
TEXT _rt0_386(SB),7,$0
// Linux, Windows 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.
PUSHL $0x27F
FLDCW 0(SP)
POPL AX
// copy arguments forward on an even stack
MOVL 0(SP), AX // argc
LEAL 4(SP), BX // argv
SUBL $128, SP // plenty of scratch
ANDL $~15, SP
MOVL AX, 120(SP) // save argc, argv away
MOVL BX, 124(SP)
// if there is an initcgo, call it to let it
// initialize and to set up GS. if not,
// we set up GS ourselves.
MOVL initcgo(SB), AX
TESTL AX, AX
JZ 4(PC)
CALL AX
CMPL runtime·iswindows(SB), $0
JEQ ok
// set up %gs
CALL runtime·ldt0setup(SB)
// store through it, to make sure it works
CMPL runtime·isplan9(SB), $1
JEQ ok
get_tls(BX)
MOVL $0x123, g(BX)
MOVL runtime·tls0(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), CX
MOVL CX, g(BX)
LEAL runtime·m0(SB), AX
MOVL AX, m(BX)
// save m->g0 = g0
MOVL CX, m_g0(AX)
// create istack out of the OS stack
LEAL (-64*1024+104)(SP), AX // TODO: 104?
MOVL AX, g_stackguard(CX)
MOVL SP, g_stackbase(CX)
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·mainstart(SB) // entry
PUSHL $0 // arg size
CALL runtime·newproc(SB)
POPL AX
POPL AX
// start this M
CALL runtime·mstart(SB)
INT $3
RET
TEXT runtime·mainstart(SB),7,$0
CALL main·init(SB)
CALL runtime·initdone(SB)
CALL main·main(SB)
PUSHL $0
CALL runtime·exit(SB)
POPL AX
INT $3
RET
TEXT runtime·breakpoint(SB),7,$0
INT $3
RET
/*
* go-routine
*/
// void gosave(Gobuf*)
// save state in Gobuf; setjmp
TEXT runtime·gosave(SB), 7, $0
MOVL 4(SP), AX // gobuf
LEAL 4(SP), BX // caller's SP
MOVL BX, gobuf_sp(AX)
MOVL 0(SP), BX // caller's PC
MOVL BX, gobuf_pc(AX)
get_tls(CX)
MOVL g(CX), BX
MOVL BX, gobuf_g(AX)
RET
// void gogo(Gobuf*, uintptr)
// restore state from Gobuf; longjmp
TEXT runtime·gogo(SB), 7, $0
MOVL 8(SP), AX // return 2nd arg
MOVL 4(SP), 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_pc(BX), BX
JMP BX
// void gogocall(Gobuf*, void (*fn)(void))
// restore state from Gobuf but then call fn.
// (call fn, returning to state in Gobuf)
TEXT runtime·gogocall(SB), 7, $0
MOVL 8(SP), AX // fn
MOVL 4(SP), BX // gobuf
MOVL gobuf_g(BX), DX
get_tls(CX)
MOVL DX, g(CX)
MOVL 0(DX), CX // make sure g != nil
MOVL gobuf_sp(BX), SP // restore SP
MOVL gobuf_pc(BX), BX
PUSHL BX
JMP AX
POPL BX // not reached
// void mcall(void (*fn)(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), 7, $0
MOVL fn+0(FP), DI
get_tls(CX)
MOVL g(CX), AX // save state in g->gobuf
MOVL 0(SP), BX // caller's PC
MOVL BX, (g_sched+gobuf_pc)(AX)
LEAL 4(SP), 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 m(CX), BX
MOVL m_g0(BX), SI
CMPL SI, AX // if g == m->g0 call badmcall
JNE 2(PC)
CALL runtime·badmcall(SB)
MOVL SI, g(CX) // g = m->g0
MOVL (g_sched+gobuf_sp)(SI), SP // sp = m->g0->gobuf.sp
PUSHL AX
CALL DI
POPL AX
CALL runtime·badmcall2(SB)
RET
/*
* support for morestack
*/
// Called during function prolog when more stack is needed.
TEXT runtime·morestack(SB),7,$0
// Cannot grow scheduler stack (m->g0).
get_tls(CX)
MOVL m(CX), BX
MOVL m_g0(BX), SI
CMPL g(CX), SI
JNE 2(PC)
INT $3
// frame size in DX
// arg size in AX
// Save in m.
MOVL DX, m_moreframesize(BX)
MOVL AX, m_moreargsize(BX)
// 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)
MOVL CX, m_moreargp(BX)
get_tls(CX)
MOVL g(CX), SI
MOVL SI, (m_morebuf+gobuf_g)(BX)
// Set m->morepc to f's PC.
MOVL 0(SP), AX
MOVL AX, m_morepc(BX)
// 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)
MOVL $0, 0x1003 // crash if newstack returns
RET
// Called from reflection library. Mimics morestack,
// reuses stack growth code to create a frame
// with the desired args running the desired function.
//
// func call(fn *byte, arg *byte, argsize uint32).
TEXT reflect·call(SB), 7, $0
get_tls(CX)
MOVL m(CX), BX
// Save our caller's state as the PC and SP to
// restore when returning from f.
MOVL 0(SP), AX // our caller's PC
MOVL AX, (m_morebuf+gobuf_pc)(BX)
LEAL 4(SP), AX // our caller's SP
MOVL AX, (m_morebuf+gobuf_sp)(BX)
MOVL g(CX), AX
MOVL AX, (m_morebuf+gobuf_g)(BX)
// Set up morestack arguments to call f on a new stack.
// We set f's frame size to 1, as a hint to newstack
// that this is a call from reflect·call.
// If it turns out that f needs a larger frame than
// the default stack, f's usual stack growth prolog will
// allocate a new segment (and recopy the arguments).
MOVL 4(SP), AX // fn
MOVL 8(SP), DX // arg frame
MOVL 12(SP), CX // arg size
MOVL AX, m_morepc(BX) // f's PC
MOVL DX, m_moreargp(BX) // f's argument pointer
MOVL CX, m_moreargsize(BX) // f's argument size
MOVL $1, m_moreframesize(BX) // f's frame size
// Call newstack on m->g0's stack.
MOVL m_g0(BX), BP
get_tls(CX)
MOVL BP, g(CX)
MOVL (g_sched+gobuf_sp)(BP), SP
CALL runtime·newstack(SB)
MOVL $0, 0x1103 // crash if newstack returns
RET
// Return point when leaving stack.
TEXT runtime·lessstack(SB), 7, $0
// Save return value in m->cret
get_tls(CX)
MOVL m(CX), BX
MOVL AX, m_cret(BX)
// Call oldstack on m->g0's stack.
MOVL m_g0(BX), BP
MOVL BP, g(CX)
MOVL (g_sched+gobuf_sp)(BP), SP
CALL runtime·oldstack(SB)
MOVL $0, 0x1004 // crash if oldstack returns
RET
// bool cas(int32 *val, int32 old, int32 new)
// Atomically:
// if(*val == old){
// *val = new;
// return 1;
// }else
// return 0;
TEXT runtime·cas(SB), 7, $0
MOVL 4(SP), BX
MOVL 8(SP), AX
MOVL 12(SP), CX
LOCK
CMPXCHGL CX, 0(BX)
JZ 3(PC)
MOVL $0, AX
RET
MOVL $1, AX
RET
// bool casp(void **p, void *old, void *new)
// Atomically:
// if(*p == old){
// *p = new;
// return 1;
// }else
// return 0;
TEXT runtime·casp(SB), 7, $0
MOVL 4(SP), BX
MOVL 8(SP), AX
MOVL 12(SP), CX
LOCK
CMPXCHGL CX, 0(BX)
JZ 3(PC)
MOVL $0, AX
RET
MOVL $1, AX
RET
// void jmpdefer(fn, sp);
// called from deferreturn.
// 1. pop the caller
// 2. sub 5 bytes from the callers return
// 3. jmp to the argument
TEXT runtime·jmpdefer(SB), 7, $0
MOVL 4(SP), AX // fn
MOVL 8(SP), BX // caller sp
LEAL -4(BX), SP // caller sp after CALL
SUBL $5, (SP) // return to CALL again
JMP AX // but first run the deferred function
// Dummy function to use in saved gobuf.PC,
// to match SP pointing at a return address.
// The gobuf.PC is unused by the contortions here
// but setting it to return will make the traceback code work.
TEXT return<>(SB),7,$0
RET
// asmcgocall(void(*fn)(void*), void *arg)
// Call fn(arg) on the scheduler stack,
// aligned appropriately for the gcc ABI.
// See cgocall.c for more details.
TEXT runtime·asmcgocall(SB),7,$0
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 m(CX), BP
MOVL m_g0(BP), SI
MOVL g(CX), DI
CMPL SI, DI
JEQ 6(PC)
MOVL SP, (g_sched+gobuf_sp)(DI)
MOVL $return<>(SB), (g_sched+gobuf_pc)(DI)
MOVL DI, (g_sched+gobuf_g)(DI)
MOVL SI, g(CX)
MOVL (g_sched+gobuf_sp)(SI), SP
// 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 DX, 4(SP) // save SP
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 DI, g(CX)
MOVL 4(SP), SP
RET
// cgocallback(void (*fn)(void*), void *frame, uintptr framesize)
// See cgocall.c for more details.
TEXT runtime·cgocallback(SB),7,$12
MOVL fn+0(FP), AX
MOVL frame+4(FP), BX
MOVL framesize+8(FP), DX
// Save current m->g0->sched.sp on stack and then set it to SP.
get_tls(CX)
MOVL m(CX), BP
MOVL m_g0(BP), SI
PUSHL (g_sched+gobuf_sp)(SI)
MOVL SP, (g_sched+gobuf_sp)(SI)
// Switch to m->curg stack and call runtime.cgocallback
// with the three arguments. 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->gobuf)
// so that we can restore it when we're done.
// We can restore m->curg->gobuf.sp easily, because calling
// runtime.cgocallback leaves SP unchanged upon return.
// To save m->curg->gobuf.pc, we push it onto the stack.
// This has the added benefit that it looks to the traceback
// routine like cgocallback is going to return to that
// PC (because we defined cgocallback to have
// a frame size of 12, the same amount that we use below),
// 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
// Push gobuf.pc
MOVL (g_sched+gobuf_pc)(SI), BP
SUBL $4, DI
MOVL BP, 0(DI)
// Push arguments to cgocallbackg.
// Frame size here must match the frame size above
// to trick traceback routines into doing the right thing.
SUBL $12, DI
MOVL AX, 0(DI)
MOVL BX, 4(DI)
MOVL DX, 8(DI)
// Switch stack and make the call.
MOVL DI, SP
CALL runtime·cgocallbackg(SB)
// Restore g->gobuf (== m->curg->gobuf) 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 m(CX), BP
MOVL m_g0(BP), SI
MOVL SI, g(CX)
MOVL (g_sched+gobuf_sp)(SI), SP
POPL (g_sched+gobuf_sp)(SI)
// Done!
RET
// check that SP is in range [g->stackbase, g->stackguard)
TEXT runtime·stackcheck(SB), 7, $0
get_tls(CX)
MOVL g(CX), AX
CMPL g_stackbase(AX), SP
JHI 2(PC)
INT $3
CMPL SP, g_stackguard(AX)
JHI 2(PC)
INT $3
RET
TEXT runtime·memclr(SB),7,$0
MOVL 4(SP), DI // arg 1 addr
MOVL 8(SP), CX // arg 2 count
ADDL $3, CX
SHRL $2, CX
MOVL $0, AX
CLD
REP
STOSL
RET
TEXT runtime·getcallerpc(SB),7,$0
MOVL x+0(FP),AX // addr of first arg
MOVL -4(AX),AX // get calling pc
RET
TEXT runtime·setcallerpc(SB),7,$0
MOVL x+0(FP),AX // addr of first arg
MOVL x+4(FP), BX
MOVL BX, -4(AX) // set calling pc
RET
TEXT runtime·getcallersp(SB), 7, $0
MOVL sp+0(FP), AX
RET
TEXT runtime·ldt0setup(SB),7,$16
// set up ldt 7 to point at tls0
// 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·tls0(SB), AX
MOVL AX, 4(SP)
MOVL $32, 8(SP) // sizeof(tls array)
CALL runtime·setldt(SB)
RET
TEXT runtime·emptyfunc(SB),0,$0
RET
TEXT runtime·abort(SB),7,$0
INT $0x3
GLOBL runtime·tls0(SB), $32