arch/arm/lib/io-readsb.S

Source file repositories/reference/linux-study-clean/arch/arm/lib/io-readsb.S

File Facts

System
Linux kernel
Corpus path
arch/arm/lib/io-readsb.S
Extension
.S
Size
2358 bytes
Lines
121
Domain
Architecture Layer
Bucket
arch/arm
Inferred role
Architecture Layer: arch/arm
Status
atlas-only

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

#include <linux/linkage.h>
#include <asm/assembler.h>

.Linsb_align:	rsb	ip, ip, #4
		cmp	ip, r2
		movgt	ip, r2
		cmp	ip, #2
		ldrb	r3, [r0]
		strb	r3, [r1], #1
		ldrbge	r3, [r0]
		strbge	r3, [r1], #1
		ldrbgt	r3, [r0]
		strbgt	r3, [r1], #1
		subs	r2, r2, ip
		bne	.Linsb_aligned

ENTRY(__raw_readsb)
		teq	r2, #0		@ do we have to check for the zero len?
		reteq	lr
		ands	ip, r1, #3
		bne	.Linsb_align

.Linsb_aligned:	stmfd	sp!, {r4 - r6, lr}

		subs	r2, r2, #16
		bmi	.Linsb_no_16

.Linsb_16_lp:	ldrb	r3, [r0]
		ldrb	r4, [r0]
		ldrb	r5, [r0]
		mov	r3, r3,     put_byte_0
		ldrb	r6, [r0]
		orr	r3, r3, r4, put_byte_1
		ldrb	r4, [r0]
		orr	r3, r3, r5, put_byte_2
		ldrb	r5, [r0]
		orr	r3, r3, r6, put_byte_3
		ldrb	r6, [r0]
		mov	r4, r4,     put_byte_0
		ldrb	ip, [r0]
		orr	r4, r4, r5, put_byte_1
		ldrb	r5, [r0]
		orr	r4, r4, r6, put_byte_2
		ldrb	r6, [r0]
		orr	r4, r4, ip, put_byte_3
		ldrb	ip, [r0]
		mov	r5, r5,     put_byte_0
		ldrb	lr, [r0]
		orr	r5, r5, r6, put_byte_1
		ldrb	r6, [r0]
		orr	r5, r5, ip, put_byte_2
		ldrb	ip, [r0]
		orr	r5, r5, lr, put_byte_3
		ldrb	lr, [r0]
		mov	r6, r6,     put_byte_0
		orr	r6, r6, ip, put_byte_1
		ldrb	ip, [r0]
		orr	r6, r6, lr, put_byte_2
		orr	r6, r6, ip, put_byte_3
		stmia	r1!, {r3 - r6}

		subs	r2, r2, #16
		bpl	.Linsb_16_lp

		tst	r2, #15
		ldmfdeq	sp!, {r4 - r6, pc}

.Linsb_no_16:	tst	r2, #8
		beq	.Linsb_no_8

Annotation

Implementation Notes