/* Optimized memcmp implementation for POWER7/PowerPC32. Copyright (C) 2010-2021 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. The GNU C Library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with the GNU C Library; if not, see . */ #include /* int [r3] memcmp (const char *s1 [r3], const char *s2 [r4], size_t size [r5]) */ .machine power7 EALIGN (memcmp, 4, 0) CALL_MCOUNT #define rRTN r3 #define rSTR1 r3 /* first string arg */ #define rSTR2 r4 /* second string arg */ #define rN r5 /* max string length */ #define rWORD1 r6 /* current word in s1 */ #define rWORD2 r7 /* current word in s2 */ #define rWORD3 r8 /* next word in s1 */ #define rWORD4 r9 /* next word in s2 */ #define rWORD5 r10 /* next word in s1 */ #define rWORD6 r11 /* next word in s2 */ #define rWORD7 r30 /* next word in s1 */ #define rWORD8 r31 /* next word in s2 */ xor r0, rSTR2, rSTR1 cmplwi cr6, rN, 0 cmplwi cr1, rN, 12 clrlwi. r0, r0, 30 clrlwi r12, rSTR1, 30 cmplwi cr5, r12, 0 beq- cr6, L(zeroLength) dcbt 0, rSTR1 dcbt 0, rSTR2 /* If less than 8 bytes or not aligned, use the unaligned byte loop. */ blt cr1, L(bytealigned) stwu 1, -64(r1) cfi_adjust_cfa_offset(64) stw rWORD8, 48(r1) stw rWORD7, 44(r1) cfi_offset(rWORD8, (48-64)) cfi_offset(rWORD7, (44-64)) bne L(unaligned) /* At this point we know both strings have the same alignment and the compare length is at least 8 bytes. r12 contains the low order 2 bits of rSTR1 and cr5 contains the result of the logical compare of r12 to 0. If r12 == 0 then we are already word aligned and can perform the word aligned loop. Otherwise we know the two strings have the same alignment (but not yet word aligned). So we force the string addresses to the next lower word boundary and special case this first word using shift left to eliminate bits preceding the first byte. Since we want to join the normal (word aligned) compare loop, starting at the second word, we need to adjust the length (rN) and special case the loop versioning for the first word. This ensures that the loop count is correct and the first word (shifted) is in the expected register pair. */ .align 4 L(samealignment): clrrwi rSTR1, rSTR1, 2 clrrwi rSTR2, rSTR2, 2 beq cr5, L(Waligned) add rN, rN, r12 slwi rWORD6, r12, 3 srwi r0, rN, 4 /* Divide by 16 */ andi. r12, rN, 12 /* Get the word remainder */ #ifdef __LITTLE_ENDIAN__ lwbrx rWORD1, 0, rSTR1 lwbrx rWORD2, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwz rWORD1, 0(rSTR1) lwz rWORD2, 0(rSTR2) #endif cmplwi cr1, r12, 8 cmplwi cr7, rN, 16 clrlwi rN, rN, 30 beq L(dPs4) mtctr r0 bgt cr1, L(dPs3) beq cr1, L(dPs2) /* Remainder is 4 */ .align 3 L(dsP1): slw rWORD5, rWORD1, rWORD6 slw rWORD6, rWORD2, rWORD6 cmplw cr5, rWORD5, rWORD6 blt cr7, L(dP1x) /* Do something useful in this cycle since we have to branch anyway. */ #ifdef __LITTLE_ENDIAN__ lwbrx rWORD1, 0, rSTR1 lwbrx rWORD2, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwz rWORD1, 4(rSTR1) lwz rWORD2, 4(rSTR2) #endif cmplw cr7, rWORD1, rWORD2 b L(dP1e) /* Remainder is 8 */ .align 4 L(dPs2): slw rWORD5, rWORD1, rWORD6 slw rWORD6, rWORD2, rWORD6 cmplw cr6, rWORD5, rWORD6 blt cr7, L(dP2x) /* Do something useful in this cycle since we have to branch anyway. */ #ifdef __LITTLE_ENDIAN__ lwbrx rWORD7, 0, rSTR1 lwbrx rWORD8, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwz rWORD7, 4(rSTR1) lwz rWORD8, 4(rSTR2) #endif cmplw cr5, rWORD7, rWORD8 b L(dP2e) /* Remainder is 12 */ .align 4 L(dPs3): slw rWORD3, rWORD1, rWORD6 slw rWORD4, rWORD2, rWORD6 cmplw cr1, rWORD3, rWORD4 b L(dP3e) /* Count is a multiple of 16, remainder is 0 */ .align 4 L(dPs4): mtctr r0 slw rWORD1, rWORD1, rWORD6 slw rWORD2, rWORD2, rWORD6 cmplw cr7, rWORD1, rWORD2 b L(dP4e) /* At this point we know both strings are word aligned and the compare length is at least 8 bytes. */ .align 4 L(Waligned): andi. r12, rN, 12 /* Get the word remainder */ srwi r0, rN, 4 /* Divide by 16 */ cmplwi cr1, r12, 8 cmplwi cr7, rN, 16 clrlwi rN, rN, 30 beq L(dP4) bgt cr1, L(dP3) beq cr1, L(dP2) /* Remainder is 4 */ .align 4 L(dP1): mtctr r0 /* Normally we'd use rWORD7/rWORD8 here, but since we might exit early (8-15 byte compare), we want to use only volatile registers. This means we can avoid restoring non-volatile registers since we did not change any on the early exit path. The key here is the non-early exit path only cares about the condition code (cr5), not about which register pair was used. */ #ifdef __LITTLE_ENDIAN__ lwbrx rWORD5, 0, rSTR1 lwbrx rWORD6, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwz rWORD5, 0(rSTR1) lwz rWORD6, 0(rSTR2) #endif cmplw cr5, rWORD5, rWORD6 blt cr7, L(dP1x) #ifdef __LITTLE_ENDIAN__ lwbrx rWORD1, 0, rSTR1 lwbrx rWORD2, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwz rWORD1, 4(rSTR1) lwz rWORD2, 4(rSTR2) #endif cmplw cr7, rWORD1, rWORD2 L(dP1e): #ifdef __LITTLE_ENDIAN__ lwbrx rWORD3, 0, rSTR1 lwbrx rWORD4, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwz rWORD3, 8(rSTR1) lwz rWORD4, 8(rSTR2) #endif cmplw cr1, rWORD3, rWORD4 #ifdef __LITTLE_ENDIAN__ lwbrx rWORD5, 0, rSTR1 lwbrx rWORD6, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwz rWORD5, 12(rSTR1) lwz rWORD6, 12(rSTR2) #endif cmplw cr6, rWORD5, rWORD6 bne cr5, L(dLcr5x) bne cr7, L(dLcr7x) #ifdef __LITTLE_ENDIAN__ lwbrx rWORD7, 0, rSTR1 lwbrx rWORD8, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwzu rWORD7, 16(rSTR1) lwzu rWORD8, 16(rSTR2) #endif bne cr1, L(dLcr1) cmplw cr5, rWORD7, rWORD8 bdnz L(dLoop) bne cr6, L(dLcr6) lwz rWORD7, 44(r1) lwz rWORD8, 48(r1) .align 3 L(dP1x): slwi. r12, rN, 3 bne cr5, L(dLcr5x) subfic rN, r12, 32 /* Shift count is 32 - (rN * 8). */ addi r1, r1, 64 cfi_adjust_cfa_offset(-64) bne L(d00) li rRTN, 0 blr /* Remainder is 8 */ .align 4 cfi_adjust_cfa_offset(64) L(dP2): mtctr r0 #ifdef __LITTLE_ENDIAN__ lwbrx rWORD5, 0, rSTR1 lwbrx rWORD6, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwz rWORD5, 0(rSTR1) lwz rWORD6, 0(rSTR2) #endif cmplw cr6, rWORD5, rWORD6 blt cr7, L(dP2x) #ifdef __LITTLE_ENDIAN__ lwbrx rWORD7, 0, rSTR1 lwbrx rWORD8, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwz rWORD7, 4(rSTR1) lwz rWORD8, 4(rSTR2) #endif cmplw cr5, rWORD7, rWORD8 L(dP2e): #ifdef __LITTLE_ENDIAN__ lwbrx rWORD1, 0, rSTR1 lwbrx rWORD2, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwz rWORD1, 8(rSTR1) lwz rWORD2, 8(rSTR2) #endif cmplw cr7, rWORD1, rWORD2 #ifdef __LITTLE_ENDIAN__ lwbrx rWORD3, 0, rSTR1 lwbrx rWORD4, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwz rWORD3, 12(rSTR1) lwz rWORD4, 12(rSTR2) #endif cmplw cr1, rWORD3, rWORD4 #ifndef __LITTLE_ENDIAN__ addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #endif bne cr6, L(dLcr6) bne cr5, L(dLcr5) b L(dLoop2) /* Again we are on a early exit path (16-23 byte compare), we want to only use volatile registers and avoid restoring non-volatile registers. */ .align 4 L(dP2x): #ifdef __LITTLE_ENDIAN__ lwbrx rWORD3, 0, rSTR1 lwbrx rWORD4, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwz rWORD3, 4(rSTR1) lwz rWORD4, 4(rSTR2) #endif cmplw cr1, rWORD3, rWORD4 slwi. r12, rN, 3 bne cr6, L(dLcr6x) #ifndef __LITTLE_ENDIAN__ addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #endif bne cr1, L(dLcr1x) subfic rN, r12, 32 /* Shift count is 32 - (rN * 8). */ addi r1, r1, 64 cfi_adjust_cfa_offset(-64) bne L(d00) li rRTN, 0 blr /* Remainder is 12 */ .align 4 cfi_adjust_cfa_offset(64) L(dP3): mtctr r0 #ifdef __LITTLE_ENDIAN__ lwbrx rWORD3, 0, rSTR1 lwbrx rWORD4, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwz rWORD3, 0(rSTR1) lwz rWORD4, 0(rSTR2) #endif cmplw cr1, rWORD3, rWORD4 L(dP3e): #ifdef __LITTLE_ENDIAN__ lwbrx rWORD5, 0, rSTR1 lwbrx rWORD6, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwz rWORD5, 4(rSTR1) lwz rWORD6, 4(rSTR2) #endif cmplw cr6, rWORD5, rWORD6 blt cr7, L(dP3x) #ifdef __LITTLE_ENDIAN__ lwbrx rWORD7, 0, rSTR1 lwbrx rWORD8, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwz rWORD7, 8(rSTR1) lwz rWORD8, 8(rSTR2) #endif cmplw cr5, rWORD7, rWORD8 #ifdef __LITTLE_ENDIAN__ lwbrx rWORD1, 0, rSTR1 lwbrx rWORD2, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwz rWORD1, 12(rSTR1) lwz rWORD2, 12(rSTR2) #endif cmplw cr7, rWORD1, rWORD2 #ifndef __LITTLE_ENDIAN__ addi rSTR1, rSTR1, 8 addi rSTR2, rSTR2, 8 #endif bne cr1, L(dLcr1) bne cr6, L(dLcr6) b L(dLoop1) /* Again we are on a early exit path (24-31 byte compare), we want to only use volatile registers and avoid restoring non-volatile registers. */ .align 4 L(dP3x): #ifdef __LITTLE_ENDIAN__ lwbrx rWORD1, 0, rSTR1 lwbrx rWORD2, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwz rWORD1, 8(rSTR1) lwz rWORD2, 8(rSTR2) #endif cmplw cr7, rWORD1, rWORD2 slwi. r12, rN, 3 bne cr1, L(dLcr1x) #ifndef __LITTLE_ENDIAN__ addi rSTR1, rSTR1, 8 addi rSTR2, rSTR2, 8 #endif bne cr6, L(dLcr6x) subfic rN, r12, 32 /* Shift count is 32 - (rN * 8). */ bne cr7, L(dLcr7x) addi r1, r1, 64 cfi_adjust_cfa_offset(-64) bne L(d00) li rRTN, 0 blr /* Count is a multiple of 16, remainder is 0 */ .align 4 cfi_adjust_cfa_offset(64) L(dP4): mtctr r0 #ifdef __LITTLE_ENDIAN__ lwbrx rWORD1, 0, rSTR1 lwbrx rWORD2, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwz rWORD1, 0(rSTR1) lwz rWORD2, 0(rSTR2) #endif cmplw cr7, rWORD1, rWORD2 L(dP4e): #ifdef __LITTLE_ENDIAN__ lwbrx rWORD3, 0, rSTR1 lwbrx rWORD4, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwz rWORD3, 4(rSTR1) lwz rWORD4, 4(rSTR2) #endif cmplw cr1, rWORD3, rWORD4 #ifdef __LITTLE_ENDIAN__ lwbrx rWORD5, 0, rSTR1 lwbrx rWORD6, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwz rWORD5, 8(rSTR1) lwz rWORD6, 8(rSTR2) #endif cmplw cr6, rWORD5, rWORD6 #ifdef __LITTLE_ENDIAN__ lwbrx rWORD7, 0, rSTR1 lwbrx rWORD8, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwzu rWORD7, 12(rSTR1) lwzu rWORD8, 12(rSTR2) #endif cmplw cr5, rWORD7, rWORD8 bne cr7, L(dLcr7) bne cr1, L(dLcr1) bdz- L(d24) /* Adjust CTR as we start with +4 */ /* This is the primary loop */ .align 4 L(dLoop): #ifdef __LITTLE_ENDIAN__ lwbrx rWORD1, 0, rSTR1 lwbrx rWORD2, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwz rWORD1, 4(rSTR1) lwz rWORD2, 4(rSTR2) #endif cmplw cr1, rWORD3, rWORD4 bne cr6, L(dLcr6) L(dLoop1): #ifdef __LITTLE_ENDIAN__ lwbrx rWORD3, 0, rSTR1 lwbrx rWORD4, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwz rWORD3, 8(rSTR1) lwz rWORD4, 8(rSTR2) #endif cmplw cr6, rWORD5, rWORD6 bne cr5, L(dLcr5) L(dLoop2): #ifdef __LITTLE_ENDIAN__ lwbrx rWORD5, 0, rSTR1 lwbrx rWORD6, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwz rWORD5, 12(rSTR1) lwz rWORD6, 12(rSTR2) #endif cmplw cr5, rWORD7, rWORD8 bne cr7, L(dLcr7) L(dLoop3): #ifdef __LITTLE_ENDIAN__ lwbrx rWORD7, 0, rSTR1 lwbrx rWORD8, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwzu rWORD7, 16(rSTR1) lwzu rWORD8, 16(rSTR2) #endif bne cr1, L(dLcr1) cmplw cr7, rWORD1, rWORD2 bdnz L(dLoop) L(dL4): cmplw cr1, rWORD3, rWORD4 bne cr6, L(dLcr6) cmplw cr6, rWORD5, rWORD6 bne cr5, L(dLcr5) cmplw cr5, rWORD7, rWORD8 L(d44): bne cr7, L(dLcr7) L(d34): bne cr1, L(dLcr1) L(d24): bne cr6, L(dLcr6) L(d14): slwi. r12, rN, 3 bne cr5, L(dLcr5) L(d04): lwz rWORD7, 44(r1) lwz rWORD8, 48(r1) addi r1, r1, 64 cfi_adjust_cfa_offset(-64) subfic rN, r12, 32 /* Shift count is 32 - (rN * 8). */ beq L(zeroLength) /* At this point we have a remainder of 1 to 3 bytes to compare. Since we are aligned it is safe to load the whole word, and use shift right to eliminate bits beyond the compare length. */ L(d00): #ifdef __LITTLE_ENDIAN__ lwbrx rWORD1, 0, rSTR1 lwbrx rWORD2, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwz rWORD1, 4(rSTR1) lwz rWORD2, 4(rSTR2) #endif srw rWORD1, rWORD1, rN srw rWORD2, rWORD2, rN sub rRTN, rWORD1, rWORD2 blr .align 4 cfi_adjust_cfa_offset(64) L(dLcr7): lwz rWORD7, 44(r1) lwz rWORD8, 48(r1) L(dLcr7x): li rRTN, 1 addi r1, r1, 64 cfi_adjust_cfa_offset(-64) bgtlr cr7 li rRTN, -1 blr .align 4 cfi_adjust_cfa_offset(64) L(dLcr1): lwz rWORD7, 44(r1) lwz rWORD8, 48(r1) L(dLcr1x): li rRTN, 1 addi r1, r1, 64 cfi_adjust_cfa_offset(-64) bgtlr cr1 li rRTN, -1 blr .align 4 cfi_adjust_cfa_offset(64) L(dLcr6): lwz rWORD7, 44(r1) lwz rWORD8, 48(r1) L(dLcr6x): li rRTN, 1 addi r1, r1, 64 cfi_adjust_cfa_offset(-64) bgtlr cr6 li rRTN, -1 blr .align 4 cfi_adjust_cfa_offset(64) L(dLcr5): lwz rWORD7, 44(r1) lwz rWORD8, 48(r1) L(dLcr5x): li rRTN, 1 addi r1, r1, 64 cfi_adjust_cfa_offset(-64) bgtlr cr5 li rRTN, -1 blr .align 4 L(bytealigned): mtctr rN /* We need to prime this loop. This loop is swing modulo scheduled to avoid pipe delays. The dependent instruction latencies (load to compare to conditional branch) is 2 to 3 cycles. In this loop each dispatch group ends in a branch and takes 1 cycle. Effectively the first iteration of the loop only serves to load operands and branches based on compares are delayed until the next loop. So we must precondition some registers and condition codes so that we don't exit the loop early on the first iteration. */ lbz rWORD1, 0(rSTR1) lbz rWORD2, 0(rSTR2) bdz L(b11) cmplw cr7, rWORD1, rWORD2 lbz rWORD3, 1(rSTR1) lbz rWORD4, 1(rSTR2) bdz L(b12) cmplw cr1, rWORD3, rWORD4 lbzu rWORD5, 2(rSTR1) lbzu rWORD6, 2(rSTR2) bdz L(b13) .align 4 L(bLoop): lbzu rWORD1, 1(rSTR1) lbzu rWORD2, 1(rSTR2) bne cr7, L(bLcr7) cmplw cr6, rWORD5, rWORD6 bdz L(b3i) lbzu rWORD3, 1(rSTR1) lbzu rWORD4, 1(rSTR2) bne cr1, L(bLcr1) cmplw cr7, rWORD1, rWORD2 bdz L(b2i) lbzu rWORD5, 1(rSTR1) lbzu rWORD6, 1(rSTR2) bne cr6, L(bLcr6) cmplw cr1, rWORD3, rWORD4 bdnz L(bLoop) /* We speculatively loading bytes before we have tested the previous bytes. But we must avoid overrunning the length (in the ctr) to prevent these speculative loads from causing a segfault. In this case the loop will exit early (before the all pending bytes are tested. In this case we must complete the pending operations before returning. */ L(b1i): bne cr7, L(bLcr7) bne cr1, L(bLcr1) b L(bx56) .align 4 L(b2i): bne cr6, L(bLcr6) bne cr7, L(bLcr7) b L(bx34) .align 4 L(b3i): bne cr1, L(bLcr1) bne cr6, L(bLcr6) b L(bx12) .align 4 L(bLcr7): li rRTN, 1 bgtlr cr7 li rRTN, -1 blr L(bLcr1): li rRTN, 1 bgtlr cr1 li rRTN, -1 blr L(bLcr6): li rRTN, 1 bgtlr cr6 li rRTN, -1 blr L(b13): bne cr7, L(bx12) bne cr1, L(bx34) L(bx56): sub rRTN, rWORD5, rWORD6 blr nop L(b12): bne cr7, L(bx12) L(bx34): sub rRTN, rWORD3, rWORD4 blr L(b11): L(bx12): sub rRTN, rWORD1, rWORD2 blr .align 4 L(zeroLength): li rRTN, 0 blr .align 4 /* At this point we know the strings have different alignment and the compare length is at least 8 bytes. r12 contains the low order 2 bits of rSTR1 and cr5 contains the result of the logical compare of r12 to 0. If r12 == 0 then rStr1 is word aligned and can perform the Wunaligned loop. Otherwise we know that rSTR1 is not already word aligned yet. So we can force the string addresses to the next lower word boundary and special case this first word using shift left to eliminate bits preceding the first byte. Since we want to join the normal (Wualigned) compare loop, starting at the second word, we need to adjust the length (rN) and special case the loop versioning for the first W. This ensures that the loop count is correct and the first W (shifted) is in the expected resister pair. */ #define rSHL r29 /* Unaligned shift left count. */ #define rSHR r28 /* Unaligned shift right count. */ #define rWORD8_SHIFT r27 /* Left rotation temp for rWORD2. */ #define rWORD2_SHIFT r26 /* Left rotation temp for rWORD4. */ #define rWORD4_SHIFT r25 /* Left rotation temp for rWORD6. */ #define rWORD6_SHIFT r24 /* Left rotation temp for rWORD8. */ cfi_adjust_cfa_offset(64) L(unaligned): stw rSHL, 40(r1) cfi_offset(rSHL, (40-64)) clrlwi rSHL, rSTR2, 30 stw rSHR, 36(r1) cfi_offset(rSHR, (36-64)) beq cr5, L(Wunaligned) stw rWORD8_SHIFT, 32(r1) cfi_offset(rWORD8_SHIFT, (32-64)) /* Adjust the logical start of rSTR2 to compensate for the extra bits in the 1st rSTR1 W. */ sub rWORD8_SHIFT, rSTR2, r12 /* But do not attempt to address the W before that W that contains the actual start of rSTR2. */ clrrwi rSTR2, rSTR2, 2 stw rWORD2_SHIFT, 28(r1) /* Compute the left/right shift counts for the unaligned rSTR2, compensating for the logical (W aligned) start of rSTR1. */ clrlwi rSHL, rWORD8_SHIFT, 30 clrrwi rSTR1, rSTR1, 2 stw rWORD4_SHIFT, 24(r1) slwi rSHL, rSHL, 3 cmplw cr5, rWORD8_SHIFT, rSTR2 add rN, rN, r12 slwi rWORD6, r12, 3 stw rWORD6_SHIFT, 20(r1) cfi_offset(rWORD2_SHIFT, (28-64)) cfi_offset(rWORD4_SHIFT, (24-64)) cfi_offset(rWORD6_SHIFT, (20-64)) subfic rSHR, rSHL, 32 srwi r0, rN, 4 /* Divide by 16 */ andi. r12, rN, 12 /* Get the W remainder */ /* We normally need to load 2 Ws to start the unaligned rSTR2, but in this special case those bits may be discarded anyway. Also we must avoid loading a W where none of the bits are part of rSTR2 as this may cross a page boundary and cause a page fault. */ li rWORD8, 0 blt cr5, L(dus0) #ifdef __LITTLE_ENDIAN__ lwbrx rWORD8, 0, rSTR2 addi rSTR2, rSTR2, 4 #else lwz rWORD8, 0(rSTR2) addi rSTR2, rSTR2, 4 #endif slw rWORD8, rWORD8, rSHL L(dus0): #ifdef __LITTLE_ENDIAN__ lwbrx rWORD1, 0, rSTR1 lwbrx rWORD2, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwz rWORD1, 0(rSTR1) lwz rWORD2, 0(rSTR2) #endif cmplwi cr1, r12, 8 cmplwi cr7, rN, 16 srw r12, rWORD2, rSHR clrlwi rN, rN, 30 beq L(duPs4) mtctr r0 or rWORD8, r12, rWORD8 bgt cr1, L(duPs3) beq cr1, L(duPs2) /* Remainder is 4 */ .align 4 L(dusP1): slw rWORD8_SHIFT, rWORD2, rSHL slw rWORD7, rWORD1, rWORD6 slw rWORD8, rWORD8, rWORD6 bge cr7, L(duP1e) /* At this point we exit early with the first word compare complete and remainder of 0 to 3 bytes. See L(du14) for details on how we handle the remaining bytes. */ cmplw cr5, rWORD7, rWORD8 slwi. rN, rN, 3 bne cr5, L(duLcr5) cmplw cr7, rN, rSHR beq L(duZeroReturn) li r0, 0 ble cr7, L(dutrim) #ifdef __LITTLE_ENDIAN__ lwbrx rWORD2, 0, rSTR2 addi rSTR2, rSTR2, 4 #else lwz rWORD2, 4(rSTR2) #endif srw r0, rWORD2, rSHR b L(dutrim) /* Remainder is 8 */ .align 4 L(duPs2): slw rWORD6_SHIFT, rWORD2, rSHL slw rWORD5, rWORD1, rWORD6 slw rWORD6, rWORD8, rWORD6 b L(duP2e) /* Remainder is 12 */ .align 4 L(duPs3): slw rWORD4_SHIFT, rWORD2, rSHL slw rWORD3, rWORD1, rWORD6 slw rWORD4, rWORD8, rWORD6 b L(duP3e) /* Count is a multiple of 16, remainder is 0 */ .align 4 L(duPs4): mtctr r0 or rWORD8, r12, rWORD8 slw rWORD2_SHIFT, rWORD2, rSHL slw rWORD1, rWORD1, rWORD6 slw rWORD2, rWORD8, rWORD6 b L(duP4e) /* At this point we know rSTR1 is word aligned and the compare length is at least 8 bytes. */ .align 4 L(Wunaligned): stw rWORD8_SHIFT, 32(r1) clrrwi rSTR2, rSTR2, 2 stw rWORD2_SHIFT, 28(r1) srwi r0, rN, 4 /* Divide by 16 */ stw rWORD4_SHIFT, 24(r1) andi. r12, rN, 12 /* Get the W remainder */ stw rWORD6_SHIFT, 20(r1) cfi_offset(rWORD8_SHIFT, (32-64)) cfi_offset(rWORD2_SHIFT, (28-64)) cfi_offset(rWORD4_SHIFT, (24-64)) cfi_offset(rWORD6_SHIFT, (20-64)) slwi rSHL, rSHL, 3 #ifdef __LITTLE_ENDIAN__ lwbrx rWORD6, 0, rSTR2 addi rSTR2, rSTR2, 4 lwbrx rWORD8, 0, rSTR2 addi rSTR2, rSTR2, 4 #else lwz rWORD6, 0(rSTR2) lwzu rWORD8, 4(rSTR2) #endif cmplwi cr1, r12, 8 cmplwi cr7, rN, 16 clrlwi rN, rN, 30 subfic rSHR, rSHL, 32 slw rWORD6_SHIFT, rWORD6, rSHL beq L(duP4) mtctr r0 bgt cr1, L(duP3) beq cr1, L(duP2) /* Remainder is 4 */ .align 4 L(duP1): srw r12, rWORD8, rSHR #ifdef __LITTLE_ENDIAN__ lwbrx rWORD7, 0, rSTR1 addi rSTR1, rSTR1, 4 #else lwz rWORD7, 0(rSTR1) #endif slw rWORD8_SHIFT, rWORD8, rSHL or rWORD8, r12, rWORD6_SHIFT blt cr7, L(duP1x) L(duP1e): #ifdef __LITTLE_ENDIAN__ lwbrx rWORD1, 0, rSTR1 lwbrx rWORD2, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwz rWORD1, 4(rSTR1) lwz rWORD2, 4(rSTR2) #endif cmplw cr5, rWORD7, rWORD8 srw r0, rWORD2, rSHR slw rWORD2_SHIFT, rWORD2, rSHL or rWORD2, r0, rWORD8_SHIFT #ifdef __LITTLE_ENDIAN__ lwbrx rWORD3, 0, rSTR1 lwbrx rWORD4, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwz rWORD3, 8(rSTR1) lwz rWORD4, 8(rSTR2) #endif cmplw cr7, rWORD1, rWORD2 srw r12, rWORD4, rSHR slw rWORD4_SHIFT, rWORD4, rSHL bne cr5, L(duLcr5) or rWORD4, r12, rWORD2_SHIFT #ifdef __LITTLE_ENDIAN__ lwbrx rWORD5, 0, rSTR1 lwbrx rWORD6, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwz rWORD5, 12(rSTR1) lwz rWORD6, 12(rSTR2) #endif cmplw cr1, rWORD3, rWORD4 srw r0, rWORD6, rSHR slw rWORD6_SHIFT, rWORD6, rSHL bne cr7, L(duLcr7) or rWORD6, r0, rWORD4_SHIFT cmplw cr6, rWORD5, rWORD6 b L(duLoop3) .align 4 /* At this point we exit early with the first word compare complete and remainder of 0 to 3 bytes. See L(du14) for details on how we handle the remaining bytes. */ L(duP1x): cmplw cr5, rWORD7, rWORD8 slwi. rN, rN, 3 bne cr5, L(duLcr5) cmplw cr7, rN, rSHR beq L(duZeroReturn) li r0, 0 ble cr7, L(dutrim) #ifdef __LITTLE_ENDIAN__ lwbrx rWORD2, 0, rSTR2 addi rSTR2, rSTR2, 4 #else lwz rWORD2, 8(rSTR2) #endif srw r0, rWORD2, rSHR b L(dutrim) /* Remainder is 8 */ .align 4 L(duP2): srw r0, rWORD8, rSHR #ifdef __LITTLE_ENDIAN__ lwbrx rWORD5, 0, rSTR1 addi rSTR1, rSTR1, 4 #else lwz rWORD5, 0(rSTR1) #endif or rWORD6, r0, rWORD6_SHIFT slw rWORD6_SHIFT, rWORD8, rSHL L(duP2e): #ifdef __LITTLE_ENDIAN__ lwbrx rWORD7, 0, rSTR1 lwbrx rWORD8, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwz rWORD7, 4(rSTR1) lwz rWORD8, 4(rSTR2) #endif cmplw cr6, rWORD5, rWORD6 srw r12, rWORD8, rSHR slw rWORD8_SHIFT, rWORD8, rSHL or rWORD8, r12, rWORD6_SHIFT blt cr7, L(duP2x) #ifdef __LITTLE_ENDIAN__ lwbrx rWORD1, 0, rSTR1 lwbrx rWORD2, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwz rWORD1, 8(rSTR1) lwz rWORD2, 8(rSTR2) #endif cmplw cr5, rWORD7, rWORD8 bne cr6, L(duLcr6) srw r0, rWORD2, rSHR slw rWORD2_SHIFT, rWORD2, rSHL or rWORD2, r0, rWORD8_SHIFT #ifdef __LITTLE_ENDIAN__ lwbrx rWORD3, 0, rSTR1 lwbrx rWORD4, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwz rWORD3, 12(rSTR1) lwz rWORD4, 12(rSTR2) #endif cmplw cr7, rWORD1, rWORD2 bne cr5, L(duLcr5) srw r12, rWORD4, rSHR slw rWORD4_SHIFT, rWORD4, rSHL or rWORD4, r12, rWORD2_SHIFT #ifndef __LITTLE_ENDIAN__ addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #endif cmplw cr1, rWORD3, rWORD4 b L(duLoop2) .align 4 L(duP2x): cmplw cr5, rWORD7, rWORD8 #ifndef __LITTLE_ENDIAN__ addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #endif bne cr6, L(duLcr6) slwi. rN, rN, 3 bne cr5, L(duLcr5) cmplw cr7, rN, rSHR beq L(duZeroReturn) li r0, 0 ble cr7, L(dutrim) #ifdef __LITTLE_ENDIAN__ lwbrx rWORD2, 0, rSTR2 addi rSTR2, rSTR2, 4 #else lwz rWORD2, 4(rSTR2) #endif srw r0, rWORD2, rSHR b L(dutrim) /* Remainder is 12 */ .align 4 L(duP3): srw r12, rWORD8, rSHR #ifdef __LITTLE_ENDIAN__ lwbrx rWORD3, 0, rSTR1 addi rSTR1, rSTR1, 4 #else lwz rWORD3, 0(rSTR1) #endif slw rWORD4_SHIFT, rWORD8, rSHL or rWORD4, r12, rWORD6_SHIFT L(duP3e): #ifdef __LITTLE_ENDIAN__ lwbrx rWORD5, 0, rSTR1 lwbrx rWORD6, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwz rWORD5, 4(rSTR1) lwz rWORD6, 4(rSTR2) #endif cmplw cr1, rWORD3, rWORD4 srw r0, rWORD6, rSHR slw rWORD6_SHIFT, rWORD6, rSHL or rWORD6, r0, rWORD4_SHIFT #ifdef __LITTLE_ENDIAN__ lwbrx rWORD7, 0, rSTR1 lwbrx rWORD8, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwz rWORD7, 8(rSTR1) lwz rWORD8, 8(rSTR2) #endif cmplw cr6, rWORD5, rWORD6 bne cr1, L(duLcr1) srw r12, rWORD8, rSHR slw rWORD8_SHIFT, rWORD8, rSHL or rWORD8, r12, rWORD6_SHIFT blt cr7, L(duP3x) #ifdef __LITTLE_ENDIAN__ lwbrx rWORD1, 0, rSTR1 lwbrx rWORD2, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwz rWORD1, 12(rSTR1) lwz rWORD2, 12(rSTR2) #endif cmplw cr5, rWORD7, rWORD8 bne cr6, L(duLcr6) srw r0, rWORD2, rSHR slw rWORD2_SHIFT, rWORD2, rSHL or rWORD2, r0, rWORD8_SHIFT #ifndef __LITTLE_ENDIAN__ addi rSTR1, rSTR1, 8 addi rSTR2, rSTR2, 8 #endif cmplw cr7, rWORD1, rWORD2 b L(duLoop1) .align 4 L(duP3x): #ifndef __LITTLE_ENDIAN__ addi rSTR1, rSTR1, 8 addi rSTR2, rSTR2, 8 #endif #if 0 /* Huh? We've already branched on cr1! */ bne cr1, L(duLcr1) #endif cmplw cr5, rWORD7, rWORD8 bne cr6, L(duLcr6) slwi. rN, rN, 3 bne cr5, L(duLcr5) cmplw cr7, rN, rSHR beq L(duZeroReturn) li r0, 0 ble cr7, L(dutrim) #ifdef __LITTLE_ENDIAN__ lwbrx rWORD2, 0, rSTR2 addi rSTR2, rSTR2, 4 #else lwz rWORD2, 4(rSTR2) #endif srw r0, rWORD2, rSHR b L(dutrim) /* Count is a multiple of 16, remainder is 0 */ .align 4 L(duP4): mtctr r0 srw r0, rWORD8, rSHR #ifdef __LITTLE_ENDIAN__ lwbrx rWORD1, 0, rSTR1 addi rSTR1, rSTR1, 4 #else lwz rWORD1, 0(rSTR1) #endif slw rWORD2_SHIFT, rWORD8, rSHL or rWORD2, r0, rWORD6_SHIFT L(duP4e): #ifdef __LITTLE_ENDIAN__ lwbrx rWORD3, 0, rSTR1 lwbrx rWORD4, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwz rWORD3, 4(rSTR1) lwz rWORD4, 4(rSTR2) #endif cmplw cr7, rWORD1, rWORD2 srw r12, rWORD4, rSHR slw rWORD4_SHIFT, rWORD4, rSHL or rWORD4, r12, rWORD2_SHIFT #ifdef __LITTLE_ENDIAN__ lwbrx rWORD5, 0, rSTR1 lwbrx rWORD6, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwz rWORD5, 8(rSTR1) lwz rWORD6, 8(rSTR2) #endif cmplw cr1, rWORD3, rWORD4 bne cr7, L(duLcr7) srw r0, rWORD6, rSHR slw rWORD6_SHIFT, rWORD6, rSHL or rWORD6, r0, rWORD4_SHIFT #ifdef __LITTLE_ENDIAN__ lwbrx rWORD7, 0, rSTR1 lwbrx rWORD8, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwzu rWORD7, 12(rSTR1) lwzu rWORD8, 12(rSTR2) #endif cmplw cr6, rWORD5, rWORD6 bne cr1, L(duLcr1) srw r12, rWORD8, rSHR slw rWORD8_SHIFT, rWORD8, rSHL or rWORD8, r12, rWORD6_SHIFT cmplw cr5, rWORD7, rWORD8 bdz L(du24) /* Adjust CTR as we start with +4 */ /* This is the primary loop */ .align 4 L(duLoop): #ifdef __LITTLE_ENDIAN__ lwbrx rWORD1, 0, rSTR1 lwbrx rWORD2, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwz rWORD1, 4(rSTR1) lwz rWORD2, 4(rSTR2) #endif cmplw cr1, rWORD3, rWORD4 bne cr6, L(duLcr6) srw r0, rWORD2, rSHR slw rWORD2_SHIFT, rWORD2, rSHL or rWORD2, r0, rWORD8_SHIFT L(duLoop1): #ifdef __LITTLE_ENDIAN__ lwbrx rWORD3, 0, rSTR1 lwbrx rWORD4, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwz rWORD3, 8(rSTR1) lwz rWORD4, 8(rSTR2) #endif cmplw cr6, rWORD5, rWORD6 bne cr5, L(duLcr5) srw r12, rWORD4, rSHR slw rWORD4_SHIFT, rWORD4, rSHL or rWORD4, r12, rWORD2_SHIFT L(duLoop2): #ifdef __LITTLE_ENDIAN__ lwbrx rWORD5, 0, rSTR1 lwbrx rWORD6, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwz rWORD5, 12(rSTR1) lwz rWORD6, 12(rSTR2) #endif cmplw cr5, rWORD7, rWORD8 bne cr7, L(duLcr7) srw r0, rWORD6, rSHR slw rWORD6_SHIFT, rWORD6, rSHL or rWORD6, r0, rWORD4_SHIFT L(duLoop3): #ifdef __LITTLE_ENDIAN__ lwbrx rWORD7, 0, rSTR1 lwbrx rWORD8, 0, rSTR2 addi rSTR1, rSTR1, 4 addi rSTR2, rSTR2, 4 #else lwzu rWORD7, 16(rSTR1) lwzu rWORD8, 16(rSTR2) #endif cmplw cr7, rWORD1, rWORD2 bne cr1, L(duLcr1) srw r12, rWORD8, rSHR slw rWORD8_SHIFT, rWORD8, rSHL or rWORD8, r12, rWORD6_SHIFT bdnz L(duLoop) L(duL4): #if 0 /* Huh? We've already branched on cr1! */ bne cr1, L(duLcr1) #endif cmplw cr1, rWORD3, rWORD4 bne cr6, L(duLcr6) cmplw cr6, rWORD5, rWORD6 bne cr5, L(duLcr5) cmplw cr5, rWORD7, rWORD8 L(du44): bne cr7, L(duLcr7) L(du34): bne cr1, L(duLcr1) L(du24): bne cr6, L(duLcr6) L(du14): slwi. rN, rN, 3 bne cr5, L(duLcr5) /* At this point we have a remainder of 1 to 3 bytes to compare. We use shift right to eliminate bits beyond the compare length. This allows the use of word subtract to compute the final result. However it may not be safe to load rWORD2 which may be beyond the string length. So we compare the bit length of the remainder to the right shift count (rSHR). If the bit count is less than or equal we do not need to load rWORD2 (all significant bits are already in rWORD8_SHIFT). */ cmplw cr7, rN, rSHR beq L(duZeroReturn) li r0, 0 ble cr7, L(dutrim) #ifdef __LITTLE_ENDIAN__ lwbrx rWORD2, 0, rSTR2 addi rSTR2, rSTR2, 4 #else lwz rWORD2, 4(rSTR2) #endif srw r0, rWORD2, rSHR .align 4 L(dutrim): #ifdef __LITTLE_ENDIAN__ lwbrx rWORD1, 0, rSTR1 #else lwz rWORD1, 4(rSTR1) #endif lwz rWORD8, 48(r1) subfic rN, rN, 32 /* Shift count is 32 - (rN * 8). */ or rWORD2, r0, rWORD8_SHIFT lwz rWORD7, 44(r1) lwz rSHL, 40(r1) srw rWORD1, rWORD1, rN srw rWORD2, rWORD2, rN lwz rSHR, 36(r1) lwz rWORD8_SHIFT, 32(r1) sub rRTN, rWORD1, rWORD2 b L(dureturn26) .align 4 L(duLcr7): lwz rWORD8, 48(r1) lwz rWORD7, 44(r1) li rRTN, 1 bgt cr7, L(dureturn29) lwz rSHL, 40(r1) lwz rSHR, 36(r1) li rRTN, -1 b L(dureturn27) .align 4 L(duLcr1): lwz rWORD8, 48(r1) lwz rWORD7, 44(r1) li rRTN, 1 bgt cr1, L(dureturn29) lwz rSHL, 40(r1) lwz rSHR, 36(r1) li rRTN, -1 b L(dureturn27) .align 4 L(duLcr6): lwz rWORD8, 48(r1) lwz rWORD7, 44(r1) li rRTN, 1 bgt cr6, L(dureturn29) lwz rSHL, 40(r1) lwz rSHR, 36(r1) li rRTN, -1 b L(dureturn27) .align 4 L(duLcr5): lwz rWORD8, 48(r1) lwz rWORD7, 44(r1) li rRTN, 1 bgt cr5, L(dureturn29) lwz rSHL, 40(r1) lwz rSHR, 36(r1) li rRTN, -1 b L(dureturn27) .align 3 L(duZeroReturn): li rRTN, 0 .align 4 L(dureturn): lwz rWORD8, 48(r1) lwz rWORD7, 44(r1) L(dureturn29): lwz rSHL, 40(r1) lwz rSHR, 36(r1) L(dureturn27): lwz rWORD8_SHIFT, 32(r1) L(dureturn26): lwz rWORD2_SHIFT, 28(r1) L(dureturn25): lwz rWORD4_SHIFT, 24(r1) lwz rWORD6_SHIFT, 20(r1) addi r1, r1, 64 cfi_adjust_cfa_offset(-64) blr END (memcmp) libc_hidden_builtin_def (memcmp) weak_alias (memcmp, bcmp) strong_alias (memcmp, __memcmpeq) libc_hidden_def (__memcmpeq)