/* * Author: Anton Blanchard * Copyright 2015 IBM Corporation. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. */ #include #include #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 #else #define LH lhzx #define LW lwzx #define LD ldx #endif /* * There are 2 categories for memcmp: * 1) src/dst has the same offset to the 8 bytes boundary. The handlers * are named like .Lsameoffset_xxxx * 2) src/dst has different offset to the 8 bytes boundary. The handlers * are named like .Ldiffoffset_xxxx */ _GLOBAL(memcmp) cmpdi cr1,r5,0 /* Use the short loop if the src/dst addresses are not * with the same offset of 8 bytes align boundary. */ xor r6,r3,r4 andi. r6,r6,7 /* Fall back to short loop if compare at aligned addrs * with less than 8 bytes. */ cmpdi cr6,r5,7 beq cr1,.Lzero bgt cr6,.Lno_short .Lshort: mtctr r5 1: lbz rA,0(r3) lbz rB,0(r4) subf. rC,rB,rA bne .Lnon_zero bdz .Lzero lbz rA,1(r3) lbz rB,1(r4) subf. rC,rB,rA bne .Lnon_zero bdz .Lzero lbz rA,2(r3) lbz rB,2(r4) subf. rC,rB,rA bne .Lnon_zero bdz .Lzero lbz rA,3(r3) lbz rB,3(r4) subf. rC,rB,rA bne .Lnon_zero addi r3,r3,4 addi r4,r4,4 bdnz 1b .Lzero: li r3,0 blr .Lno_short: dcbt 0,r3 dcbt 0,r4 bne .Ldiffoffset_8bytes_make_align_start .Lsameoffset_8bytes_make_align_start: /* attempt to compare bytes not aligned with 8 bytes so that * rest comparison can run based on 8 bytes alignment. */ andi. r6,r3,7 /* Try to compare the first double word which is not 8 bytes aligned: * load the first double word at (src & ~7UL) and shift left appropriate * bits before comparision. */ rlwinm r6,r3,3,26,28 beq .Lsameoffset_8bytes_aligned clrrdi r3,r3,3 clrrdi r4,r4,3 LD rA,0,r3 LD rB,0,r4 sld rA,rA,r6 sld rB,rB,r6 cmpld cr0,rA,rB srwi r6,r6,3 bne cr0,.LcmpAB_lightweight subfic r6,r6,8 subf. r5,r6,r5 addi r3,r3,8 addi r4,r4,8 beq .Lzero .Lsameoffset_8bytes_aligned: /* now we are aligned with 8 bytes. * Use .Llong loop if left cmp bytes are equal or greater than 32B. */ cmpdi cr6,r5,31 bgt cr6,.Llong .Lcmp_lt32bytes: /* compare 1 ~ 32 bytes, at least r3 addr is 8 bytes aligned now */ cmpdi cr5,r5,7 srdi r0,r5,3 ble cr5,.Lcmp_rest_lt8bytes /* handle 8 ~ 31 bytes */ clrldi r5,r5,61 mtctr r0 2: LD rA,0,r3 LD rB,0,r4 cmpld cr0,rA,rB addi r3,r3,8 addi r4,r4,8 bne cr0,.LcmpAB_lightweight bdnz 2b cmpwi r5,0 beq .Lzero .Lcmp_rest_lt8bytes: /* Here we have only less than 8 bytes to compare with. at least s1 * Address is aligned with 8 bytes. * The next double words are load and shift right with appropriate * bits. */ subfic r6,r5,8 slwi r6,r6,3 LD rA,0,r3 LD rB,0,r4 srd rA,rA,r6 srd rB,rB,r6 cmpld cr0,rA,rB bne cr0,.LcmpAB_lightweight b .Lzero .Lnon_zero: mr r3,rC blr .Llong: /* At least s1 addr is aligned with 8 bytes */ li off8,8 li off16,16 li off24,24 std r31,-8(r1) std r30,-16(r1) std r29,-24(r1) std r28,-32(r1) std r27,-40(r1) srdi r0,r5,5 mtctr r0 andi. r5,r5,31 LD rA,0,r3 LD rB,0,r4 LD rC,off8,r3 LD rD,off8,r4 LD rE,off16,r3 LD rF,off16,r4 LD rG,off24,r3 LD rH,off24,r4 cmpld cr0,rA,rB addi r3,r3,32 addi r4,r4,32 bdz .Lfirst32 LD rA,0,r3 LD rB,0,r4 cmpld cr1,rC,rD LD rC,off8,r3 LD rD,off8,r4 cmpld cr6,rE,rF LD rE,off16,r3 LD rF,off16,r4 cmpld cr7,rG,rH bne cr0,.LcmpAB LD rG,off24,r3 LD rH,off24,r4 cmpld cr0,rA,rB bne cr1,.LcmpCD addi r3,r3,32 addi r4,r4,32 bdz .Lsecond32 .balign 16 1: LD rA,0,r3 LD rB,0,r4 cmpld cr1,rC,rD bne cr6,.LcmpEF LD rC,off8,r3 LD rD,off8,r4 cmpld cr6,rE,rF bne cr7,.LcmpGH LD rE,off16,r3 LD rF,off16,r4 cmpld cr7,rG,rH bne cr0,.LcmpAB LD rG,off24,r3 LD rH,off24,r4 cmpld cr0,rA,rB bne cr1,.LcmpCD addi r3,r3,32 addi r4,r4,32 bdnz 1b .Lsecond32: cmpld cr1,rC,rD bne cr6,.LcmpEF cmpld cr6,rE,rF bne cr7,.LcmpGH cmpld cr7,rG,rH bne cr0,.LcmpAB bne cr1,.LcmpCD bne cr6,.LcmpEF bne cr7,.LcmpGH .Ltail: ld r31,-8(r1) ld r30,-16(r1) ld r29,-24(r1) ld r28,-32(r1) ld r27,-40(r1) cmpdi r5,0 beq .Lzero b .Lshort .Lfirst32: cmpld cr1,rC,rD cmpld cr6,rE,rF cmpld cr7,rG,rH bne cr0,.LcmpAB bne cr1,.LcmpCD bne cr6,.LcmpEF bne cr7,.LcmpGH b .Ltail .LcmpAB: li r3,1 bgt cr0,.Lout li r3,-1 b .Lout .LcmpCD: li r3,1 bgt cr1,.Lout li r3,-1 b .Lout .LcmpEF: li r3,1 bgt cr6,.Lout li r3,-1 b .Lout .LcmpGH: li r3,1 bgt cr7,.Lout li r3,-1 .Lout: ld r31,-8(r1) ld r30,-16(r1) ld r29,-24(r1) ld r28,-32(r1) ld r27,-40(r1) blr .LcmpAB_lightweight: /* skip NV GPRS restore */ li r3,1 bgtlr li r3,-1 blr .Ldiffoffset_8bytes_make_align_start: /* now try to align s1 with 8 bytes */ rlwinm r6,r3,3,26,28 beq .Ldiffoffset_align_s1_8bytes clrrdi r3,r3,3 LD rA,0,r3 LD rB,0,r4 /* unaligned load */ sld rA,rA,r6 srd rA,rA,r6 srd rB,rB,r6 cmpld cr0,rA,rB srwi r6,r6,3 bne cr0,.LcmpAB_lightweight subfic r6,r6,8 subf. r5,r6,r5 addi r3,r3,8 add r4,r4,r6 beq .Lzero .Ldiffoffset_align_s1_8bytes: /* now s1 is aligned with 8 bytes. */ cmpdi cr5,r5,31 ble cr5,.Lcmp_lt32bytes b .Llong EXPORT_SYMBOL(memcmp)