58 lines
1.4 KiB
ArmAsm
58 lines
1.4 KiB
ArmAsm
|
// Copyright (c) 2026 Petr Balvín <opensource@petrbalvin.org> (https://petrbalvin.org)
|
||
|
|
// SPDX-License-Identifier: BSD-3-Clause
|
||
|
|
|
||
|
|
#include "textflag.h"
|
||
|
|
|
||
|
|
// The link-regression kernel for arm64, the amd64 one's sibling: stack
|
||
|
|
// discipline (add), an intra-file branch with link (probe calling seven,
|
||
|
|
// R_CALLARM64), an ADRP+ADD pair against static data (word<>,
|
||
|
|
// R_ADDRARM64), a symbol-valued DATA field (entry holding seven's
|
||
|
|
// address, R_ADDR), NOPTR data outside the GC's type scan (counter) and
|
||
|
|
// the data section itself. The callee's result slot sits at the caller's
|
||
|
|
// SP+8, the arm64 ABI0 frame convention.
|
||
|
|
|
||
|
|
// func add(a, b int64) int64
|
||
|
|
TEXT ·add(SB), NOSPLIT, $0-24
|
||
|
|
MOVD a+0(FP), R0
|
||
|
|
MOVD b+8(FP), R1
|
||
|
|
ADD R1, R0, R0
|
||
|
|
MOVD R0, ret+16(FP)
|
||
|
|
RET
|
||
|
|
|
||
|
|
// func seven() int64
|
||
|
|
TEXT ·seven(SB), NOSPLIT, $0-8
|
||
|
|
MOVD $7, R0
|
||
|
|
MOVD R0, ret+0(FP)
|
||
|
|
RET
|
||
|
|
|
||
|
|
// func probe() int64 = seven() + word<>(SB)
|
||
|
|
TEXT ·probe(SB), NOSPLIT, $8-8
|
||
|
|
BL ·seven(SB)
|
||
|
|
MOVD 8(RSP), R0
|
||
|
|
MOVD $word<>(SB), R4
|
||
|
|
MOVD (R4), R5
|
||
|
|
ADD R5, R0, R0
|
||
|
|
MOVD R0, ret+0(FP)
|
||
|
|
RET
|
||
|
|
|
||
|
|
// func entryAddr() uintptr
|
||
|
|
TEXT ·entryAddr(SB), NOSPLIT, $0-8
|
||
|
|
MOVD entry(SB), R4
|
||
|
|
MOVD R4, ret+0(FP)
|
||
|
|
RET
|
||
|
|
|
||
|
|
// func counterVal() int64
|
||
|
|
TEXT ·counterVal(SB), NOSPLIT, $0-8
|
||
|
|
MOVD counter(SB), R4
|
||
|
|
MOVD R4, ret+0(FP)
|
||
|
|
RET
|
||
|
|
|
||
|
|
GLOBL word<>(SB), RODATA, $8
|
||
|
|
DATA word<>+0(SB)/8, $0x0fedcba987654321
|
||
|
|
|
||
|
|
GLOBL entry(SB), RODATA, $8
|
||
|
|
DATA entry+0(SB)/8, $·seven(SB)
|
||
|
|
|
||
|
|
GLOBL counter(SB), NOPTR, $8
|
||
|
|
DATA counter+0(SB)/8, $1234
|