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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 "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
// 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
* 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)
// 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
// 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)
* 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 $-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 $0, R1 // c = 0
MOVW R1, -16(SP)
MOVW 4(FP), R1 // n
MOVW R1, -12(SP)
MOVW m, -8(SP) // Save m and g
MOVW g, -4(SP)
BL runtime·memset(SB)
MOVW -8(SP), m // Restore m and g, memset clobbers them
MOVW -4(SP), g
TEXT runtime·getcallerpc(SB),7,$-4
MOVW 0(SP), R0
TEXT runtime·setcallerpc(SB),7,$-4
MOVW x+4(FP), R0
MOVW R0, 0(SP)
TEXT runtime·getcallersp(SB),7,$-4
MOVW 0(FP), R0
MOVW $-4(R0), R0
TEXT runtime·emptyfunc(SB),0,$0
TEXT runtime·abort(SB),7,$-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
LDREX (R1), R0
CMP R0, R2
BNE casfail
STREX R3, (R1), R0
CMP $0, R0
BNE casl
MOVW $1, R0
MOVW $0, R0