tools/testing/selftests/arm64/fp/asm-utils.S

Source file repositories/reference/linux-study-clean/tools/testing/selftests/arm64/fp/asm-utils.S

File Facts

System
Linux kernel
Corpus path
tools/testing/selftests/arm64/fp/asm-utils.S
Extension
.S
Size
2831 bytes
Lines
173
Domain
Support Tooling And Documentation
Bucket
tools
Inferred role
Support Tooling And Documentation: tools
Status
atlas-only

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0-only
// Copyright (C) 2015-2021 ARM Limited.
// Original author: Dave Martin <Dave.Martin@arm.com>
//
// Utility functions for assembly code.

#include <asm/unistd.h>
#include "assembler.h"

// Print a single character x0 to stdout
// Clobbers x0-x2,x8
function putc
	str	x0, [sp, #-16]!

	mov	x0, #1			// STDOUT_FILENO
	mov	x1, sp
	mov	x2, #1
	mov	x8, #__NR_write
	svc	#0

	add	sp, sp, #16
	ret
endfunction
.globl	putc
	
// Print a NUL-terminated string starting at address x0 to stdout
// Clobbers x0-x3,x8
function puts
	mov	x1, x0

	mov	x2, #0
0:	ldrb	w3, [x0], #1
	cbz	w3, 1f
	add	x2, x2, #1
	b	0b

1:	mov	w0, #1			// STDOUT_FILENO
	mov	x8, #__NR_write
	svc	#0

	ret
endfunction
.globl	puts

// Print an unsigned decimal number x0 to stdout
// Clobbers x0-x4,x8
function putdec
	mov	x1, sp
	str	x30, [sp, #-32]!	// Result can't be > 20 digits

	mov	x2, #0
	strb	w2, [x1, #-1]!		// Write the NUL terminator

	mov	x2, #10
0:	udiv	x3, x0, x2		// div-mod loop to generate the digits
	msub	x0, x3, x2, x0
	add	w0, w0, #'0'
	strb	w0, [x1, #-1]!
	mov	x0, x3
	cbnz	x3, 0b

	ldrb	w0, [x1]
	cbnz	w0, 1f
	mov	w0, #'0'		// Print "0" for 0, not ""
	strb	w0, [x1, #-1]!

1:	mov	x0, x1
	bl	puts

	ldr	x30, [sp], #32

Annotation

Implementation Notes