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253 lines
6.7 KiB
253 lines
6.7 KiB
Backport of |
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commit 72607db038df1a1a7987af814aad8d2ed466c45c |
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Author: Rajalakshmi Srinivasaraghavan <raji@linux.vnet.ibm.com> |
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Date: Fri Jan 9 11:56:35 2015 -0500 |
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powerpc: Optimize POWER7 strcmp trailing checks |
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This patch optimized the POWER7 trailing check by avoiding using byte |
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read operations and instead use the doubleword already readed with |
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bitwise operations. |
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ChangeLog: |
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2015-01-13 Rajalakshmi Srinivasaraghavan <raji@linux.vnet.ibm.com> |
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Adhemerval Zanella <azanella@linux.vnet.ibm.com> |
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* sysdeps/powerpc/powerpc64/power7/strcmp.S (strcmp): Optimize |
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trailing byte check. |
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diff --git a/sysdeps/powerpc/powerpc64/power7/strcmp.S b/sysdeps/powerpc/powerpc64/power7/strcmp.S |
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index f16a9d8..ade2811 100644 |
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--- a/sysdeps/powerpc/powerpc64/power7/strcmp.S |
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+++ b/sysdeps/powerpc/powerpc64/power7/strcmp.S |
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@@ -25,122 +25,96 @@ |
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/* int [r3] strcmp (const char *s1 [r3], const char *s2 [r4]) */ |
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+ .machine power7 |
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EALIGN (strcmp, 4, 0) |
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CALL_MCOUNT 2 |
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or r9, r3, r4 |
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rldicl. r10, r9, 0, 61 /* are s1 and s2 8 byte aligned..? */ |
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bne cr0, L(process_unaligned_bytes) |
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+ li r5, 0 |
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+ .align 4 |
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/* process input parameters on double word aligned boundary */ |
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- ld r9, 0(r4) /* load s2 at offset=0 */ |
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- li r10, 0 /* load mask=0 */ |
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- cmpb r10, r9, r10 /* compare bytes at s2 with mask */ |
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- cmpdi cr7, r10, 0 /* is NULL found ..? is end of string HIT */ |
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- bne cr7, L(process_unaligned_bytes) /* process byte by byte */ |
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- |
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- ld r10, 0(r3) /* load s1 at offset=0 */ |
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- li r8, 0 /* load mask=0 */ |
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- cmpb r8, r10, r8 /* compare bytes at s1 with mask */ |
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- cmpdi cr7, r8, 0 /* is NULL found ..? is end of string HIT */ |
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- bne cr7, L(process_unaligned_bytes) /* process byte by byte */ |
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- |
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-/*s1 and s2 does not contain NULL now , so compare all 8 bytes in a GO */ |
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- cmpb r9, r10, r9 /* compare s1 and s2 */ |
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- cmpdi cr7, r9, -1 /* compare result with 0xFFFFFFFFFFFFFFFF */ |
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- bne cr7, L(process_unaligned_bytes) /* s1,s2 mismatch found */ |
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- |
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- addi r5, r3, 8 /* save next offset of s2 */ |
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- addi r11, r4, 8 /* save next offset of s1 */ |
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- ld r8, 8(r4) /* load s2 at offset=8 */ |
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- li r9, 0 /* load mask=0 */ |
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- cmpb r9, r8, r9 /* compare bytes at s2 with mask */ |
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- cmpdi cr7, r9, 0 /* NULL found ..? */ |
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- bne cr7, L(processBytes)/* update input and process bytes one by one */ |
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- |
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- mr r9, r4 /* save s2 */ |
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- li r10, 0 /* load mask=0 */ |
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- |
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- ld r7, 8(r3) /* load s1 at offset=8 */ |
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- cmpb r6, r7, r10 /* compare bytes at s1 with mask */ |
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- cmpdi cr7, r6, 0 /* is NULL found */ |
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- bne cr7, L(processBytes)/* mismatch, so process one by one */ |
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- |
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L(unrollDword): |
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- cmpb r8, r7, r8 /* compare s1 and s2 */ |
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- cmpdi cr7, r8, -1 /* compare result with 0xFFFFFFFFFFFFFFFF */ |
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- bne cr7, L(processBytes)/* mismatch with s1 and s2 */ |
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- |
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- addi r5, r3, 16 /* save offset=16 of s1 */ |
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- addi r4, r9, 16 /* save offset=16 of s2 */ |
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- ld r8, 16(r9) /* load s2 at offset=16 */ |
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- cmpb r7, r8, r10 /* compare bytes at s2 with mask */ |
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- cmpdi cr7, r7, 0 /* NULL found ..? */ |
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- bne cr7, L(update2processBytes) |
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- |
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- ld r7, 16(r3) /* load s1 at offset=16 */ |
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- cmpb r6, r7, r10 /* check s1 for end of string */ |
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- cmpdi cr7, r6, 0 /* end of s1 ?,then handle byte by byte */ |
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- bne 7,L(update2processBytes) |
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- |
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- cmpb r8, r7, r8 /* compare s1 and s2 double words */ |
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- cmpdi cr7, r8, -1 /* compare results with 0xFFFFFFFFFFFFFFFF */ |
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- bne cr7,L(update2processBytes) |
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- |
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- addi r5, r3, 24 /* update s1 to offset=24 */ |
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- addi r4, r9, 24 /* update s2 to offset=24 */ |
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- |
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- ld r8, 24(r9) /* load s2 */ |
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- cmpb r7, r8, r10 /* compare s2 for NULL */ |
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- cmpdi cr7, r7, 0 /* verify if s2 is ending now */ |
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- bne cr7,L(update2processBytes) |
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- |
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- ld r7, 24(r3) /* load s1 at offset=24 */ |
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- cmpb r6, r7, r10 /* verify for NULL */ |
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- cmpdi cr7, r6, 0 /* is NULL found */ |
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- bne cr7, L(update2processBytes) |
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- |
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- cmpb r8, r7, r8 /* compare s1 and s2 */ |
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- cmpdi cr7, r8, -1 /* are s1 and s2 same ..? */ |
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- bne cr7, L(update2processBytes) |
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- |
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- addi r7, r9, 32 /* update s2 to next double word */ |
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- addi r3, r3, 32 /* update s1 to next double word */ |
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- |
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- ld r8, 32(r9) /* load s2 */ |
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- mr r4, r7 /* save s2 */ |
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- cmpb r6, r8, r10 /* compare s2 with NULL */ |
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- cmpdi cr7, r6, 0 /* end of s2 ..? */ |
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- bne cr7, L(process_unaligned_bytes) |
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- |
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- ld r6, 0(r3) /* load and compare s1 for NULL */ |
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- cmpb r5, r6, r10 |
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- cmpdi cr7, r5, 0 |
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- bne cr7, L(process_unaligned_bytes) |
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- |
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- cmpb r8, r6, r8 /* compare s1 and s2 */ |
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- cmpdi cr7, r8, -1 |
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- bne cr7, L(process_unaligned_bytes) |
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- |
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- addi r5, r3, 8 /* increment s1 and d2 here */ |
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- addi r11, r9, 40 |
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- |
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- ld r8, 40(r9) /* process s2 now */ |
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- cmpb r9, r8, r10 |
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- cmpdi cr7, r9, 0 |
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- bne cr7, L(processBytes) |
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- |
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- mr r9, r7 |
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- ld r7, 8(r3) /* process s1 now */ |
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- cmpb r6, r7, r10 |
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- cmpdi cr7, r6, 0 |
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- beq cr7, L(unrollDword) /* unroll to compare s1 and s2 */ |
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- |
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-L(processBytes): |
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- mr r4, r11 /* update input params */ |
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- mr r3, r5 |
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- |
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- .p2align 4 |
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+ ld r8,0(r3) |
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+ ld r10,0(r4) |
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+ cmpb r7,r8,r5 |
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+ cmpdi cr7,r7,0 |
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+ mr r9,r7 |
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+ bne cr7,L(null_found) |
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+ cmpld cr7,r8,r10 |
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+ bne cr7,L(different) |
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+ |
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+ ld r8,8(r3) |
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+ ld r10,8(r4) |
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+ cmpb r7,r8,r5 |
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+ cmpdi cr7,r7,0 |
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+ mr r9,r7 |
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+ bne cr7,L(null_found) |
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+ cmpld cr7,r8,r10 |
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+ bne cr7,L(different) |
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+ |
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+ ld r8,16(r3) |
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+ ld r10,16(r4) |
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+ cmpb r7,r8,r5 |
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+ cmpdi cr7,r7,0 |
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+ mr r9,r7 |
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+ bne cr7,L(null_found) |
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+ cmpld cr7,r8,r10 |
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+ bne cr7,L(different) |
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+ |
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+ ld r8,24(r3) |
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+ ld r10,24(r4) |
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+ cmpb r7,r8,r5 |
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+ cmpdi cr7,r7,0 |
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+ mr r9,r7 |
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+ bne cr7,L(null_found) |
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+ cmpld cr7,r8,r10 |
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+ bne cr7,L(different) |
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+ |
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+ addi r3, r3, 32 |
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+ addi r4, r4, 32 |
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+ beq cr7, L(unrollDword) |
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+ |
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+ .align 4 |
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+L(null_found): |
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+#ifdef __LITTLE_ENDIAN__ |
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+ neg r7,r9 |
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+ and r9,r9,r7 |
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+ li r7,-1 |
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+ cntlzd r9,r9 |
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+ subfic r9,r9,71 |
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+ sld r9,r7,r9 |
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+#else |
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+ cntlzd r9,r9 |
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+ li r7,-1 |
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+ addi r9,r9,8 |
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+ srd r9,r7,r9 |
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+#endif |
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+ or r8,r8,r9 |
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+ or r10,r10,r9 |
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+ |
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+L(different): |
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+ cmpb r9,r8,r10 |
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+#ifdef __LITTLE_ENDIAN__ |
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+ addi r7,r9,1 |
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+ andc r9,r7,r9 |
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+ cntlzd r9,r9 |
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+ subfic r9,r9,63 |
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+#else |
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+ not r9,r9 |
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+ cntlzd r9,r9 |
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+ subfic r9,r9,56 |
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+#endif |
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+ srd r3,r8,r9 |
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+ srd r10,r10,r9 |
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+ rldicl r10,r10,0,56 |
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+ rldicl r3,r3,0,56 |
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+ subf r3,r10,r3 |
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+ blr |
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+ |
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+ .align 4 |
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L(process_unaligned_bytes): |
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lbz r9, 0(r3) /* load byte from s1 */ |
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lbz r10, 0(r4) /* load byte from s2 */ |
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@@ -172,24 +146,19 @@ L(process_unaligned_bytes): |
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addi r4, r4, 4 /* increment s2 by unroll factor */ |
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beq cr6, L(process_unaligned_bytes) /* unroll byte processing */ |
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- .p2align 4 |
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+ .align 4 |
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L(ComputeDiff): |
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extsw r9, r9 |
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subf r10, r10, r9 /* compute s1 - s2 */ |
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extsw r3, r10 |
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blr /* return */ |
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- .p2align 4 |
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+ .align 4 |
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L(diffOfNULL): |
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li r9, 0 |
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subf r10, r10, r9 /* compute s1 - s2 */ |
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extsw r3, r10 /* sign extend result */ |
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blr /* return */ |
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- .p2align 4 |
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-L(update2processBytes): |
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- mr r3, r5 /* update and proceed */ |
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- b L(process_unaligned_bytes) |
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- |
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END (strcmp) |
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libc_hidden_builtin_def (strcmp)
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