src/pkg/runtime/arm/asm.s - go - Git at Google


            
            // 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 "arm/asm.h"


            // using frame size $-4 means do not save LR on stack.

            
            TEXT _rt0_arm(SB),7,$-4

            
            	MOVW	$0xcafebabe, R12


            	// copy arguments forward on an even stack

            
            	// use R13 instead of SP to avoid linker rewriting the offsets

            
            	MOVW	0(R13), R0		// argc

            
            	MOVW	$4(R13), R1		// argv

            
            	SUB	$64, R13		// plenty of scratch

            
            	AND	$~7, R13

            
            	MOVW	R0, 60(R13)		// save argc, argv away

            
            	MOVW	R1, 64(R13)


            	// set up m and g registers

            
            	// g is R10, m is R9

            
            	MOVW	$runtime·g0(SB), g

            
            	MOVW	$runtime·m0(SB), m


            	// save m->g0 = g0

            
            	MOVW	g, m_g0(m)


            	// create istack out of the OS stack

            
            	MOVW	$(-8192+104)(R13), R0

            
            	MOVW	R0, g_stackguard(g)	// (w 104b guard)

            
            	MOVW	R13, g_stackbase(g)

            
            	BL	runtime·emptyfunc(SB)	// fault if stack check is wrong


            	BL	runtime·check(SB)


            	// saved argc, argv

            
            	MOVW	60(R13), R0

            
            	MOVW	R0, 4(R13)

            
            	MOVW	64(R13), R1

            
            	MOVW	R1, 8(R13)

            
            	BL	runtime·args(SB)

            
            	BL	runtime·osinit(SB)

            
            	BL	runtime·schedinit(SB)


            	// create a new goroutine to start program

            
            	MOVW	$runtime·mainstart(SB), R0

            
            	MOVW.W	R0, -4(R13)

            
            	MOVW	$8, R0

            
            	MOVW.W	R0, -4(R13)

            
            	MOVW	$0, R0

            
            	MOVW.W	R0, -4(R13)	// push $0 as guard

            
            	BL	runtime·newproc(SB)

            
            	MOVW	$12(R13), R13	// pop args and LR


            	// start this M

            
            	BL	runtime·mstart(SB)


            	MOVW	$1234, R0

            
            	MOVW	$1000, R1

            
            	MOVW	R0, (R1)	// fail hard

            
            	B	runtime·_dep_dummy(SB)	// Never reached


            TEXT runtime·mainstart(SB),7,$4

            
            	BL	main·init(SB)

            
            	BL	runtime·initdone(SB)

            
            	EOR	R0, R0

            
            	MOVW	R0, 0(R13)

            
            	BL	main·main(SB)

            
            	MOVW	$0, R0

            
            	MOVW	R0, 4(SP)

            
            	BL	runtime·exit(SB)

            
            	MOVW	$1234, R0

            
            	MOVW	$1001, R1

            
            	MOVW	R0, (R1)	// fail hard

            
            	RET


            // TODO(kaib): remove these once i actually understand how the linker removes symbols

            
            // pull in dummy dependencies

            
            TEXT runtime·_dep_dummy(SB),7,$0

            
            	BL	_div(SB)

            
            	BL	_divu(SB)

            
            	BL	_mod(SB)

            
            	BL	_modu(SB)

            
            	BL	_modu(SB)

            
            	BL	_sfloat(SB)


            TEXT runtime·breakpoint(SB),7,$0

            
            	// no breakpoint yet; let program exit

            
            	RET


            /*

            
             *  go-routine

            
             */


            // void gosave(Gobuf*)

            
            // save state in Gobuf; setjmp

            
            TEXT runtime·gosave(SB), 7, $-4

            
            	MOVW	0(FP), R0		// gobuf

            
            	MOVW	SP, gobuf_sp(R0)

            
            	MOVW	LR, gobuf_pc(R0)

            
            	MOVW	g, gobuf_g(R0)

            
            	RET


            // void gogo(Gobuf*, uintptr)

            
            // restore state from Gobuf; longjmp

            
            TEXT runtime·gogo(SB), 7, $-4

            
            	MOVW	0(FP), R1		// gobuf

            
            	MOVW	4(FP), R0		// return 2nd arg

            
            	MOVW	gobuf_g(R1), g

            
            	MOVW	0(g), R2		// make sure g != nil

            
            	MOVW	gobuf_sp(R1), SP	// restore SP

            
            	MOVW	gobuf_pc(R1), PC


            // void gogocall(Gobuf*, void (*fn)(void))

            
            // restore state from Gobuf but then call fn.

            
            // (call fn, returning to state in Gobuf)

            
            // using frame size $-4 means do not save LR on stack.

            
            TEXT runtime·gogocall(SB), 7, $-4

            
            	MOVW	0(FP), R0		// gobuf

            
            	MOVW	4(FP), R1		// fn

            
            	MOVW	8(FP), R2		// fp offset

            
            	MOVW	gobuf_g(R0), g

            
            	MOVW	0(g), R3		// make sure g != nil

            
            	MOVW	gobuf_sp(R0), SP	// restore SP

            
            	MOVW	gobuf_pc(R0), LR

            
            	MOVW	R1, PC


            // 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, $-4

            
            	MOVW	fn+0(FP), R0


            	// Save caller state in g->gobuf.

            
            	MOVW	SP, (g_sched+gobuf_sp)(g)

            
            	MOVW	LR, (g_sched+gobuf_pc)(g)

            
            	MOVW	g, (g_sched+gobuf_g)(g)


            	// Switch to m->g0 & its stack, call fn.

            
            	MOVW	g, R1

            
            	MOVW	m_g0(m), g

            
            	CMP	g, R1

            
            	BL.EQ	runtime·badmcall(SB)

            
            	MOVW	(g_sched+gobuf_sp)(g), SP

            
            	SUB	$8, SP

            
            	MOVW	R1, 4(SP)

            
            	BL	(R0)

            
            	BL	runtime·badmcall2(SB)

            
            	RET


            /*

            
             * support for morestack

            
             */


            // Called during function prolog when more stack is needed.

            
            // R1 frame size

            
            // R2 arg size

            
            // R3 prolog's LR

            
            // NB. we do not save R0 because we've forced 5c to pass all arguments

            
            // on the stack.

            
            // using frame size $-4 means do not save LR on stack.

            
            TEXT runtime·morestack(SB),7,$-4

            
            	// Cannot grow scheduler stack (m->g0).

            
            	MOVW	m_g0(m), R4

            
            	CMP	g, R4

            
            	BL.EQ	runtime·abort(SB)


            	// Save in m.

            
            	MOVW	R1, m_moreframesize(m)

            
            	MOVW	R2, m_moreargsize(m)


            	// Called from f.

            
            	// Set m->morebuf to f's caller.

            
            	MOVW	R3, (m_morebuf+gobuf_pc)(m)	// f's caller's PC

            
            	MOVW	SP, (m_morebuf+gobuf_sp)(m)	// f's caller's SP

            
            	MOVW	$4(SP), R3			// f's argument pointer

            
            	MOVW	R3, m_moreargp(m)

            
            	MOVW	g, (m_morebuf+gobuf_g)(m)


            	// Set m->morepc to f's PC.

            
            	MOVW	LR, m_morepc(m)


            	// Call newstack on m->g0's stack.

            
            	MOVW	m_g0(m), g

            
            	MOVW	(g_sched+gobuf_sp)(g), SP

            
            	B	runtime·newstack(SB)


            // 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, $-4

            
            	// Save our caller's state as the PC and SP to

            
            	// restore when returning from f.

            
            	MOVW	LR, (m_morebuf+gobuf_pc)(m)	// our caller's PC

            
            	MOVW	SP, (m_morebuf+gobuf_sp)(m)	// our caller's SP

            
            	MOVW	g,  (m_morebuf+gobuf_g)(m)


            	// 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).

            
            	MOVW	4(SP), R0			// fn

            
            	MOVW	8(SP), R1			// arg frame

            
            	MOVW	12(SP), R2			// arg size


            	MOVW	R0, m_morepc(m)			// f's PC

            
            	MOVW	R1, m_moreargp(m)		// f's argument pointer

            
            	MOVW	R2, m_moreargsize(m)		// f's argument size

            
            	MOVW	$1, R3

            
            	MOVW	R3, m_moreframesize(m)		// f's frame size


            	// Call newstack on m->g0's stack.

            
            	MOVW	m_g0(m), g

            
            	MOVW	(g_sched+gobuf_sp)(g), SP

            
            	B	runtime·newstack(SB)


            // Return point when leaving stack.

            
            // using frame size $-4 means do not save LR on stack.

            
            TEXT runtime·lessstack(SB), 7, $-4

            
            	// Save return value in m->cret

            
            	MOVW	R0, m_cret(m)


            	// Call oldstack on m->g0's stack.

            
            	MOVW	m_g0(m), g

            
            	MOVW	(g_sched+gobuf_sp)(g), SP

            
            	B	runtime·oldstack(SB)


            // void jmpdefer(fn, sp);

            
            // called from deferreturn.

            
            // 1. grab stored LR for caller

            
            // 2. sub 4 bytes to get back to BL deferreturn

            
            // 3. B to fn

            
            TEXT runtime·jmpdefer(SB), 7, $0

            
            	MOVW	0(SP), LR

            
            	MOVW	$-4(LR), LR	// BL deferreturn

            
            	MOVW	fn+0(FP), R0

            
            	MOVW	argp+4(FP), SP

            
            	MOVW	$-4(SP), SP	// SP is 4 below argp, due to saved LR

            
            	B		(R0)


            TEXT	runtime·asmcgocall(SB),7,$0

            
            	B	runtime·cgounimpl(SB)


            TEXT	runtime·cgocallback(SB),7,$0

            
            	B	runtime·cgounimpl(SB)


            TEXT runtime·memclr(SB),7,$20

            
            	MOVW	0(FP), R0

            
            	MOVW	$0, R1		// c = 0

            
            	MOVW	R1, -16(SP)

            
            	MOVW	4(FP), R1	// n

            
            	MOVW	R1, -12(SP)

            
            	MOVW	m, -8(SP)	// Save m and g

            
            	MOVW	g, -4(SP)

            
            	BL	runtime·memset(SB)

            
            	MOVW	-8(SP), m	// Restore m and g, memset clobbers them

            
            	MOVW	-4(SP), g

            
            	RET


            TEXT runtime·getcallerpc(SB),7,$-4

            
            	MOVW	0(SP), R0

            
            	RET


            TEXT runtime·setcallerpc(SB),7,$-4

            
            	MOVW	x+4(FP), R0

            
            	MOVW	R0, 0(SP)

            
            	RET


            TEXT runtime·getcallersp(SB),7,$-4

            
            	MOVW	0(FP), R0

            
            	MOVW	$-4(R0), R0

            
            	RET


            TEXT runtime·emptyfunc(SB),0,$0

            
            	RET


            TEXT runtime·abort(SB),7,$-4

            
            	MOVW	$0, R0

            
            	MOVW	(R0), R1


            // bool armcas(int32 *val, int32 old, int32 new)

            
            // Atomically:

            
            //	if(*val == old){

            
            //		*val = new;

            
            //		return 1;

            
            //	}else

            
            //		return 0;

            
            //

            
            // To implement runtime·cas in ../$GOOS/arm/sys.s

            
            // using the native instructions, use:

            
            //

            
            //	TEXT runtime·cas(SB),7,$0

            
            //		B	runtime·armcas(SB)

            
            //

            
            TEXT runtime·armcas(SB),7,$0

            
            	MOVW	valptr+0(FP), R1

            
            	MOVW	old+4(FP), R2

            
            	MOVW	new+8(FP), R3

            
            casl:

            
            	LDREX	(R1), R0

            
            	CMP		R0, R2

            
            	BNE		casfail

            
            	STREX	R3, (R1), R0

            
            	CMP		$0, R0

            
            	BNE		casl

            
            	MOVW	$1, R0

            
            	RET

            
            casfail:

            
            	MOVW	$0, R0

            
            	RET
	// 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 "arm/asm.h"

	// using frame size $-4 means do not save LR on stack.
	TEXT _rt0_arm(SB),7,$-4
	MOVW $0xcafebabe, R12

	// copy arguments forward on an even stack
	// use R13 instead of SP to avoid linker rewriting the offsets
	MOVW 0(R13), R0 // argc
	MOVW $4(R13), R1 // argv
	SUB $64, R13 // plenty of scratch
	AND $~7, R13
	MOVW R0, 60(R13) // save argc, argv away
	MOVW R1, 64(R13)

	// set up m and g registers
	// g is R10, m is R9
	MOVW $runtime·g0(SB), g
	MOVW $runtime·m0(SB), m

	// save m->g0 = g0
	MOVW g, m_g0(m)

	// create istack out of the OS stack
	MOVW $(-8192+104)(R13), R0
	MOVW R0, g_stackguard(g) // (w 104b guard)
	MOVW R13, g_stackbase(g)
	BL runtime·emptyfunc(SB) // fault if stack check is wrong

	BL runtime·check(SB)

	// saved argc, argv
	MOVW 60(R13), R0
	MOVW R0, 4(R13)
	MOVW 64(R13), R1
	MOVW R1, 8(R13)
	BL runtime·args(SB)
	BL runtime·osinit(SB)
	BL runtime·schedinit(SB)

	// create a new goroutine to start program
	MOVW $runtime·mainstart(SB), R0
	MOVW.W R0, -4(R13)
	MOVW $8, R0
	MOVW.W R0, -4(R13)
	MOVW $0, R0
	MOVW.W R0, -4(R13) // push $0 as guard
	BL runtime·newproc(SB)
	MOVW $12(R13), R13 // pop args and LR

	// start this M
	BL runtime·mstart(SB)

	MOVW $1234, R0
	MOVW $1000, R1
	MOVW R0, (R1) // fail hard
	B runtime·_dep_dummy(SB) // Never reached


	TEXT runtime·mainstart(SB),7,$4
	BL main·init(SB)
	BL runtime·initdone(SB)
	EOR R0, R0
	MOVW R0, 0(R13)
	BL main·main(SB)
	MOVW $0, R0
	MOVW R0, 4(SP)
	BL runtime·exit(SB)
	MOVW $1234, R0
	MOVW $1001, R1
	MOVW R0, (R1) // fail hard
	RET

	// TODO(kaib): remove these once i actually understand how the linker removes symbols
	// pull in dummy dependencies
	TEXT runtime·_dep_dummy(SB),7,$0
	BL _div(SB)
	BL _divu(SB)
	BL _mod(SB)
	BL _modu(SB)
	BL _modu(SB)
	BL _sfloat(SB)

	TEXT runtime·breakpoint(SB),7,$0
	// no breakpoint yet; let program exit
	RET

	/*
	* go-routine
	*/

	// void gosave(Gobuf*)
	// save state in Gobuf; setjmp
	TEXT runtime·gosave(SB), 7, $-4
	MOVW 0(FP), R0 // gobuf
	MOVW SP, gobuf_sp(R0)
	MOVW LR, gobuf_pc(R0)
	MOVW g, gobuf_g(R0)
	RET

	// void gogo(Gobuf*, uintptr)
	// restore state from Gobuf; longjmp
	TEXT runtime·gogo(SB), 7, $-4
	MOVW 0(FP), R1 // gobuf
	MOVW 4(FP), R0 // return 2nd arg
	MOVW gobuf_g(R1), g
	MOVW 0(g), R2 // make sure g != nil
	MOVW gobuf_sp(R1), SP // restore SP
	MOVW gobuf_pc(R1), PC

	// void gogocall(Gobuf, void (fn)(void))
	// restore state from Gobuf but then call fn.
	// (call fn, returning to state in Gobuf)
	// using frame size $-4 means do not save LR on stack.
	TEXT runtime·gogocall(SB), 7, $-4
	MOVW 0(FP), R0 // gobuf
	MOVW 4(FP), R1 // fn
	MOVW 8(FP), R2 // fp offset
	MOVW gobuf_g(R0), g
	MOVW 0(g), R3 // make sure g != nil
	MOVW gobuf_sp(R0), SP // restore SP
	MOVW gobuf_pc(R0), LR
	MOVW R1, PC

	// 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, $-4
	MOVW fn+0(FP), R0

	// Save caller state in g->gobuf.
	MOVW SP, (g_sched+gobuf_sp)(g)
	MOVW LR, (g_sched+gobuf_pc)(g)
	MOVW g, (g_sched+gobuf_g)(g)

	// Switch to m->g0 & its stack, call fn.
	MOVW g, R1
	MOVW m_g0(m), g
	CMP g, R1
	BL.EQ runtime·badmcall(SB)
	MOVW (g_sched+gobuf_sp)(g), SP
	SUB $8, SP
	MOVW R1, 4(SP)
	BL (R0)
	BL runtime·badmcall2(SB)
	RET

	/*
	* support for morestack
	*/

	// Called during function prolog when more stack is needed.
	// R1 frame size
	// R2 arg size
	// R3 prolog's LR
	// NB. we do not save R0 because we've forced 5c to pass all arguments
	// on the stack.
	// using frame size $-4 means do not save LR on stack.
	TEXT runtime·morestack(SB),7,$-4
	// Cannot grow scheduler stack (m->g0).
	MOVW m_g0(m), R4
	CMP g, R4
	BL.EQ runtime·abort(SB)

	// Save in m.
	MOVW R1, m_moreframesize(m)
	MOVW R2, m_moreargsize(m)

	// Called from f.
	// Set m->morebuf to f's caller.
	MOVW R3, (m_morebuf+gobuf_pc)(m) // f's caller's PC
	MOVW SP, (m_morebuf+gobuf_sp)(m) // f's caller's SP
	MOVW $4(SP), R3 // f's argument pointer
	MOVW R3, m_moreargp(m)
	MOVW g, (m_morebuf+gobuf_g)(m)

	// Set m->morepc to f's PC.
	MOVW LR, m_morepc(m)

	// Call newstack on m->g0's stack.
	MOVW m_g0(m), g
	MOVW (g_sched+gobuf_sp)(g), SP
	B runtime·newstack(SB)

	// 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, $-4
	// Save our caller's state as the PC and SP to
	// restore when returning from f.
	MOVW LR, (m_morebuf+gobuf_pc)(m) // our caller's PC
	MOVW SP, (m_morebuf+gobuf_sp)(m) // our caller's SP
	MOVW g, (m_morebuf+gobuf_g)(m)

	// 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).
	MOVW 4(SP), R0 // fn
	MOVW 8(SP), R1 // arg frame
	MOVW 12(SP), R2 // arg size

	MOVW R0, m_morepc(m) // f's PC
	MOVW R1, m_moreargp(m) // f's argument pointer
	MOVW R2, m_moreargsize(m) // f's argument size
	MOVW $1, R3
	MOVW R3, m_moreframesize(m) // f's frame size

	// Call newstack on m->g0's stack.
	MOVW m_g0(m), g
	MOVW (g_sched+gobuf_sp)(g), SP
	B runtime·newstack(SB)

	// Return point when leaving stack.
	// using frame size $-4 means do not save LR on stack.
	TEXT runtime·lessstack(SB), 7, $-4
	// Save return value in m->cret
	MOVW R0, m_cret(m)

	// Call oldstack on m->g0's stack.
	MOVW m_g0(m), g
	MOVW (g_sched+gobuf_sp)(g), SP
	B runtime·oldstack(SB)

	// void jmpdefer(fn, sp);
	// called from deferreturn.
	// 1. grab stored LR for caller
	// 2. sub 4 bytes to get back to BL deferreturn
	// 3. B to fn
	TEXT runtime·jmpdefer(SB), 7, $0
	MOVW 0(SP), LR
	MOVW $-4(LR), LR // BL deferreturn
	MOVW fn+0(FP), R0
	MOVW argp+4(FP), SP
	MOVW $-4(SP), SP // SP is 4 below argp, due to saved LR
	B (R0)

	TEXT runtime·asmcgocall(SB),7,$0
	B runtime·cgounimpl(SB)

	TEXT runtime·cgocallback(SB),7,$0
	B runtime·cgounimpl(SB)

	TEXT runtime·memclr(SB),7,$20
	MOVW 0(FP), R0
	MOVW $0, R1 // c = 0
	MOVW R1, -16(SP)
	MOVW 4(FP), R1 // n
	MOVW R1, -12(SP)
	MOVW m, -8(SP) // Save m and g
	MOVW g, -4(SP)
	BL runtime·memset(SB)
	MOVW -8(SP), m // Restore m and g, memset clobbers them
	MOVW -4(SP), g
	RET

	TEXT runtime·getcallerpc(SB),7,$-4
	MOVW 0(SP), R0
	RET

	TEXT runtime·setcallerpc(SB),7,$-4
	MOVW x+4(FP), R0
	MOVW R0, 0(SP)
	RET

	TEXT runtime·getcallersp(SB),7,$-4
	MOVW 0(FP), R0
	MOVW $-4(R0), R0
	RET

	TEXT runtime·emptyfunc(SB),0,$0
	RET

	TEXT runtime·abort(SB),7,$-4
	MOVW $0, R0
	MOVW (R0), R1

	// bool armcas(int32 *val, int32 old, int32 new)
	// Atomically:
	// if(*val == old){
	// *val = new;
	// return 1;
	// }else
	// return 0;
	//
	// To implement runtime·cas in ../$GOOS/arm/sys.s
	// using the native instructions, use:
	//
	// TEXT runtime·cas(SB),7,$0
	// B runtime·armcas(SB)
	//
	TEXT runtime·armcas(SB),7,$0
	MOVW valptr+0(FP), R1
	MOVW old+4(FP), R2
	MOVW new+8(FP), R3
	casl:
	LDREX (R1), R0
	CMP R0, R2
	BNE casfail
	STREX R3, (R1), R0
	CMP $0, R0
	BNE casl
	MOVW $1, R0
	RET
	casfail:
	MOVW $0, R0
	RET