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--- Libc/Libc-498/ppc/string/memcmp.s
+++ Libc/Libc-320/ppc/string/memcmp.s
@@ -2,6 +2,8 @@
* Copyright (c) 2002 Apple Computer, Inc. All rights reserved.
*
* @APPLE_LICENSE_HEADER_START@
+ *
+ * Copyright (c) 1999-2003 Apple Computer, Inc. All Rights Reserved.
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
@@ -24,13 +26,6 @@
#include <mach/ppc/asm.h>
#undef ASSEMBLER
-/* We use mode-independent "g" opcodes such as "srgi". These expand
- * into word operations when targeting __ppc__, and into doubleword
- * operations when targeting __ppc64__.
- */
-#include <architecture/ppc/mode_independent_asm.h>
-
-
// *************** ***********
// * M E M C M P * and * B C M P *
// *************** ***********
@@ -46,33 +41,31 @@
// finding a difference, we might get a spurious page fault by
// reading bytes past the difference. To avoid this, we never do a "lwz"
// that crosses a page boundary.
-//
-// In 64-bit mode, this routine is doubleword parallel.
.text
.globl EXT(memcmp)
.globl EXT(bcmp)
.align 5
-LEXT(memcmp) // int memcmp(const char *s1,const char *s2,size_t len);
+LEXT(memcmp) // int memcmp(const char *s1,const char *s2,size_t len);
LEXT(bcmp) // int bcmp(const char *s1,const char *s2,size_t len);
- cmplgi cr1,r5,2*GPR_BYTES // is buffer too short to bother with parallel compares?
- andi. r0,r3,GPR_BYTES-1 // is LHS aligned?
+ cmplwi cr1,r5,8 // is buffer too short to bother with word compares?
+ andi. r0,r3,3 // is LHS word aligned?
blt cr1,Lshort // short buffer, so just compare byte-by-byte
beq Laligned // skip if aligned
- subfic r0,r0,GPR_BYTES // r0 <- #bytes to align LHS
+ subfic r0,r0,4 // r0 <- #bytes to word align LHS
mtctr r0 // set up for byte loop
b Lbyteloop
// Handle short buffer or end-of-buffer.
// r3 = LHS ptr (unaligned)
// r4 = RHS ptr (unaligned)
-// r5 = length remaining in buffer (0..2*GPR_BYTES-1)
+// r5 = length remaining in buffer (0..7)
Lshort:
- cmpgi r5,0 // null buffer?
+ cmpwi r5,0 // null buffer?
mtctr r5 // assume not null, and set up for loop
- bne Lshortloop // buffer not null
+ bne Lshortloop // buffer not null
li r3,0 // say "equal"
blr
@@ -88,14 +81,14 @@
sub r3,r7,r8 // generate return value
blr
-// We're at a RHS page boundary. Compare GPR_BYTES bytes in order to cross the
-// page but still keep the LHS ptr aligned.
+// We're at a RHS page boundary. Compare 4 bytes in order to cross the
+// page but still keep the LHS ptr word-aligned.
Lcrosspage:
- cmplgi r5,2*GPR_BYTES // enough bytes left to use parallel compares?
- li r0,GPR_BYTES // get #bytes to cross RHS page
+ cmplwi r5,8 // enough bytes left to use word compares?
+ li r0,4 // get #bytes to cross RHS page
blt Lshort // buffer is about to end
- mtctr r0
+ mtctr r0 // set up to compare 4 bytes
b Lbyteloop
// Compare byte-by-byte.
@@ -114,14 +107,14 @@
cmpw r7,r8 // compare the bytes
bdnzt eq,Lbyteloop // loop if more to go and bytes are equal
- bne Ldifferent // done if we found differing bytes
+ bne Ldifferent // done if we found differing bytes
-// LHS is now aligned. Loop over words/doublewords until end of RHS page or buffer.
-// When we get to the end of the page, we compare 4/8 bytes, so that we keep
-// the LHS aligned.
+// LHS is now word aligned. Loop over words until end of RHS page or buffer.
+// When we get to the end of the page, we compare 4 bytes, so that we keep
+// the LHS word aligned.
// r3 = LHS ptr (aligned)
// r4 = RHS ptr (unaligned)
-// r5 = length remaining in buffer (>= GPR_BYTES bytes)
+// r5 = length remaining in buffer (>= 4 bytes)
Laligned:
rlwinm r9,r4,0,0xFFF // get RHS offset in page
@@ -130,45 +123,40 @@
subfe r8,r5,r5 // * r9 <- min(r0,r5),
and r7,r7,r8 // * using algorithm in Compiler Writer's Guide
add r9,r0,r7 // ***
- srgi. r8,r9,LOG2_GPR_BYTES// get #words/doublewords we can compare
- clrrgi r9,r9,LOG2_GPR_BYTES// get #bytes we will compare word-parallel
+ srwi. r8,r9,2 // get #words we can compare
+ rlwinm r9,r9,0,0,29 // get #bytes we will compare word-parallel
beq-- Lcrosspage // we're at a RHS page boundary
mtctr r8 // set up loop count
sub r5,r5,r9 // decrement length remaining
b Lwordloop
-// Compare a word or doubleword at a time, until one of two conditions:
+// Compare a word at a time, until one of two conditions:
// - a difference is found
// - end of count (ie, end of buffer or RHS page, whichever is first)
// At this point, registers are as follows:
// r3 = LHS ptr (aligned)
// r4 = RHS ptr (unaligned)
// r5 = length remaining in buffer (may be 0)
-// ctr = count of word/doublewords until end of buffer or RHS page
+// ctr = count of words until end of buffer or RHS page
- .align 5 // align inner loop
+ .align 5 // align inner loop, which is 8 words long
Lwordloop:
- lg r7,0(r3) // r7 <- next aligned LHS word or doubleword
- addi r3,r3,GPR_BYTES
- lg r8,0(r4) // r8 <- next unaligned RHS word or doubleword
- addi r4,r4,GPR_BYTES
- xor. r11,r7,r8 // compare them
+ lwz r7,0(r3) // r7 <- next 4 LHS bytes
+ addi r3,r3,4
+ lwz r8,0(r4) // r8 <- next 4 RHS bytes
+ addi r4,r4,4
+ xor. r11,r7,r8 // compare the words
bdnzt eq,Lwordloop // loop if ctr!=0 and cr0_eq
- beq Lcrosspage // skip if buffer or page end reached wo difference
+ beq-- Lcrosspage // skip if buffer or page end reached
// Found differing bytes.
- cntlzg r0,r11 // find 1st difference (r0 = 0..31 or 63)
- rlwinm r9,r0,0,0x38 // byte align bit offset (r9 = 0,8,16, or 24 etc)
- addi r0,r9,8 // now, r0 = 8, 16, 24, or 32 etc
-#if defined(__ppc__)
+ cntlzw r0,r11 // find 1st difference (r0 = 0..31)
+ rlwinm r9,r0,0,0x18 // byte align bit offset (r9 = 0,8,16, or 24)
+ addi r0,r9,8 // now, r0 = 8, 16, 24, or 32
rlwnm r7,r7,r0,24,31 // right justify differing bytes and mask off rest
rlwnm r8,r8,r0,24,31
-#else
- rldcl r7,r7,r0,56 // right justify differing bytes and mask off rest
- rldcl r8,r8,r0,56
-#endif
Ldifferent: // bytes in r7 and r8 differ
sub r3,r7,r8 // compute return value