arch/powerpc/lib/memcmp_64.S

Source file repositories/reference/linux-study-clean/arch/powerpc/lib/memcmp_64.S

File Facts

System: Linux kernel
Corpus path: arch/powerpc/lib/memcmp_64.S
Extension: .S
Size: 11708 bytes
Lines: 639
Domain: Architecture Layer
Bucket: arch/powerpc
Inferred role: Architecture Layer: exported/initcall integration point
Status: integration implementation candidate

Why This File Exists

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

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.
Exports symbols or registers init work; inspect boot/module ordering and who consumes the exported contract.

Dependency Surface

linux/export.h
asm/ppc_asm.h
asm/ppc-opcode.h

Detected Declarations

export memcmp

Annotated Snippet

#include <linux/export.h>
#include <asm/ppc_asm.h>
#include <asm/ppc-opcode.h>

#define off8	r6
#define off16	r7
#define off24	r8

#define rA	r9
#define rB	r10
#define rC	r11
#define rD	r27
#define rE	r28
#define rF	r29
#define rG	r30
#define rH	r31

#ifdef __LITTLE_ENDIAN__
#define LH	lhbrx
#define LW	lwbrx
#define LD	ldbrx
#define LVS	lvsr
#define VPERM(_VRT,_VRA,_VRB,_VRC) \
	vperm _VRT,_VRB,_VRA,_VRC
#else
#define LH	lhzx
#define LW	lwzx
#define LD	ldx
#define LVS	lvsl
#define VPERM(_VRT,_VRA,_VRB,_VRC) \
	vperm _VRT,_VRA,_VRB,_VRC
#endif

#define VMX_THRESH 4096
#define ENTER_VMX_OPS	\
	mflr    r0;	\
	std     r3,-STACKFRAMESIZE+STK_REG(R31)(r1); \
	std     r4,-STACKFRAMESIZE+STK_REG(R30)(r1); \
	std     r5,-STACKFRAMESIZE+STK_REG(R29)(r1); \
	std     r0,16(r1); \
	stdu    r1,-STACKFRAMESIZE(r1); \
	bl      CFUNC(enter_vmx_ops); \
	cmpwi   cr1,r3,0; \
	ld      r0,STACKFRAMESIZE+16(r1); \
	ld      r3,STK_REG(R31)(r1); \
	ld      r4,STK_REG(R30)(r1); \
	ld      r5,STK_REG(R29)(r1); \
	addi	r1,r1,STACKFRAMESIZE; \
	mtlr    r0

#define EXIT_VMX_OPS \
	mflr    r0; \
	std     r3,-STACKFRAMESIZE+STK_REG(R31)(r1); \
	std     r4,-STACKFRAMESIZE+STK_REG(R30)(r1); \
	std     r5,-STACKFRAMESIZE+STK_REG(R29)(r1); \
	std     r0,16(r1); \
	stdu    r1,-STACKFRAMESIZE(r1); \
	bl      CFUNC(exit_vmx_ops); \
	ld      r0,STACKFRAMESIZE+16(r1); \
	ld      r3,STK_REG(R31)(r1); \
	ld      r4,STK_REG(R30)(r1); \
	ld      r5,STK_REG(R29)(r1); \
	addi	r1,r1,STACKFRAMESIZE; \
	mtlr    r0

/*
 * LD_VSR_CROSS16B load the 2nd 16 bytes for _vaddr which is unaligned with
 * 16 bytes boundary and permute the result with the 1st 16 bytes.

 *    |  y y y y y y y y y y y y y 0 1 2 | 3 4 5 6 7 8 9 a b c d e f z z z |

Annotation

Immediate include surface: `linux/export.h`, `asm/ppc_asm.h`, `asm/ppc-opcode.h`.
Detected declarations: `export memcmp`.
Atlas domain: Architecture Layer / arch/powerpc.
Implementation status: integration implementation candidate.

Implementation Notes

This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.