aboutsummaryrefslogtreecommitdiff
path: root/REORG.TODO/sysdeps/powerpc/powerpc32/power7/strncmp.S
diff options
context:
space:
mode:
authorZack Weinberg <zackw@panix.com>2017-06-08 15:39:03 -0400
committerZack Weinberg <zackw@panix.com>2017-06-08 15:39:03 -0400
commit5046dbb4a7eba5eccfd258f92f4735c9ffc8d069 (patch)
tree4470480d904b65cf14ca524f96f79eca818c3eaf /REORG.TODO/sysdeps/powerpc/powerpc32/power7/strncmp.S
parent199fc19d3aaaf57944ef036e15904febe877fc93 (diff)
downloadglibc-5046dbb4a7eba5eccfd258f92f4735c9ffc8d069.tar
glibc-5046dbb4a7eba5eccfd258f92f4735c9ffc8d069.tar.gz
glibc-5046dbb4a7eba5eccfd258f92f4735c9ffc8d069.tar.bz2
glibc-5046dbb4a7eba5eccfd258f92f4735c9ffc8d069.zip
Prepare for radical source tree reorganization.zack/build-layout-experiment
All top-level files and directories are moved into a temporary storage directory, REORG.TODO, except for files that will certainly still exist in their current form at top level when we're done (COPYING, COPYING.LIB, LICENSES, NEWS, README), all old ChangeLog files (which are moved to the new directory OldChangeLogs, instead), and the generated file INSTALL (which is just deleted; in the new order, there will be no generated files checked into version control).
Diffstat (limited to 'REORG.TODO/sysdeps/powerpc/powerpc32/power7/strncmp.S')
-rw-r--r--REORG.TODO/sysdeps/powerpc/powerpc32/power7/strncmp.S199
1 files changed, 199 insertions, 0 deletions
diff --git a/REORG.TODO/sysdeps/powerpc/powerpc32/power7/strncmp.S b/REORG.TODO/sysdeps/powerpc/powerpc32/power7/strncmp.S
new file mode 100644
index 0000000000..d4598e1930
--- /dev/null
+++ b/REORG.TODO/sysdeps/powerpc/powerpc32/power7/strncmp.S
@@ -0,0 +1,199 @@
+/* Optimized strcmp implementation for POWER7/PowerPC32.
+ Copyright (C) 2010-2017 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
+ <http://www.gnu.org/licenses/>. */
+
+#include <sysdep.h>
+
+/* See strlen.s for comments on how the end-of-string testing works. */
+
+/* int [r3] strncmp (const char *s1 [r3],
+ const char *s2 [r4],
+ size_t size [r5]) */
+
+EALIGN (strncmp,5,0)
+
+#define rTMP2 r0
+#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 r10
+#define rWORD4 r11
+#define rFEFE r8 /* constant 0xfefefeff (-0x01010101) */
+#define r7F7F r9 /* constant 0x7f7f7f7f */
+#define rNEG r10 /* ~(word in s1 | 0x7f7f7f7f) */
+#define rBITDIF r11 /* bits that differ in s1 & s2 words */
+#define rTMP r12
+
+ dcbt 0,rSTR1
+ nop
+ or rTMP,rSTR2,rSTR1
+ lis r7F7F,0x7f7f
+ dcbt 0,rSTR2
+ nop
+ clrlwi. rTMP,rTMP,30
+ cmplwi cr1,rN,0
+ lis rFEFE,-0x101
+ bne L(unaligned)
+/* We are word aligned so set up for two loops. first a word
+ loop, then fall into the byte loop if any residual. */
+ srwi. rTMP,rN,2
+ clrlwi rN,rN,30
+ addi rFEFE,rFEFE,-0x101
+ addi r7F7F,r7F7F,0x7f7f
+ cmplwi cr1,rN,0
+ beq L(unaligned)
+
+ mtctr rTMP
+ lwz rWORD1,0(rSTR1)
+ lwz rWORD2,0(rSTR2)
+ b L(g1)
+
+L(g0):
+ lwzu rWORD1,4(rSTR1)
+ bne cr1,L(different)
+ lwzu rWORD2,4(rSTR2)
+L(g1): add rTMP,rFEFE,rWORD1
+ nor rNEG,r7F7F,rWORD1
+ bdz L(tail)
+ and. rTMP,rTMP,rNEG
+ cmpw cr1,rWORD1,rWORD2
+ beq L(g0)
+
+/* OK. We've hit the end of the string. We need to be careful that
+ we don't compare two strings as different because of gunk beyond
+ the end of the strings... */
+#ifdef __LITTLE_ENDIAN__
+L(endstring):
+ slwi rTMP, rTMP, 1
+ addi rTMP2, rTMP, -1
+ andc rTMP2, rTMP2, rTMP
+ and rWORD2, rWORD2, rTMP2 /* Mask off gunk. */
+ and rWORD1, rWORD1, rTMP2
+ rlwinm rTMP2, rWORD2, 8, 0xffffffff /* Byte reverse word. */
+ rlwinm rTMP, rWORD1, 8, 0xffffffff
+ rldimi rTMP2, rWORD2, 24, 32
+ rldimi rTMP, rWORD1, 24, 32
+ rlwimi rTMP2, rWORD2, 24, 16, 23
+ rlwimi rTMP, rWORD1, 24, 16, 23
+ xor. rBITDIF, rTMP, rTMP2
+ sub rRTN, rTMP, rTMP2
+ bgelr
+ ori rRTN, rTMP2, 1
+ blr
+
+L(different):
+ lwz rWORD1, -4(rSTR1)
+ rlwinm rTMP2, rWORD2, 8, 0xffffffff /* Byte reverse word. */
+ rlwinm rTMP, rWORD1, 8, 0xffffffff
+ rldimi rTMP2, rWORD2, 24, 32
+ rldimi rTMP, rWORD1, 24, 32
+ rlwimi rTMP2, rWORD2, 24, 16, 23
+ rlwimi rTMP, rWORD1, 24, 16, 23
+ xor. rBITDIF, rTMP, rTMP2
+ sub rRTN, rTMP, rTMP2
+ bgelr
+ ori rRTN, rTMP2, 1
+ blr
+
+#else
+L(endstring):
+ and rTMP,r7F7F,rWORD1
+ beq cr1,L(equal)
+ add rTMP,rTMP,r7F7F
+ xor. rBITDIF,rWORD1,rWORD2
+ andc rNEG,rNEG,rTMP
+ blt L(highbit)
+ cntlzw rBITDIF,rBITDIF
+ cntlzw rNEG,rNEG
+ addi rNEG,rNEG,7
+ cmpw cr1,rNEG,rBITDIF
+ sub rRTN,rWORD1,rWORD2
+ bgelr cr1
+L(equal):
+ li rRTN,0
+ blr
+
+L(different):
+ lwz rWORD1,-4(rSTR1)
+ xor. rBITDIF,rWORD1,rWORD2
+ sub rRTN,rWORD1,rWORD2
+ bgelr
+L(highbit):
+ ori rRTN, rWORD2, 1
+ blr
+#endif
+
+/* Oh well. In this case, we just do a byte-by-byte comparison. */
+ .align 4
+L(tail):
+ and. rTMP,rTMP,rNEG
+ cmpw cr1,rWORD1,rWORD2
+ bne L(endstring)
+ addi rSTR1,rSTR1,4
+ bne cr1,L(different)
+ addi rSTR2,rSTR2,4
+ cmplwi cr1,rN,0
+L(unaligned):
+ mtctr rN
+ ble cr1,L(ux)
+L(uz):
+ lbz rWORD1,0(rSTR1)
+ lbz rWORD2,0(rSTR2)
+ .align 4
+L(u1):
+ cmpwi cr1,rWORD1,0
+ bdz L(u4)
+ cmpw rWORD1,rWORD2
+ beq cr1,L(u4)
+ bne L(u4)
+ lbzu rWORD3,1(rSTR1)
+ lbzu rWORD4,1(rSTR2)
+ cmpwi cr1,rWORD3,0
+ bdz L(u3)
+ cmpw rWORD3,rWORD4
+ beq cr1,L(u3)
+ bne L(u3)
+ lbzu rWORD1,1(rSTR1)
+ lbzu rWORD2,1(rSTR2)
+ cmpwi cr1,rWORD1,0
+ bdz L(u4)
+ cmpw rWORD1,rWORD2
+ beq cr1,L(u4)
+ bne L(u4)
+ lbzu rWORD3,1(rSTR1)
+ lbzu rWORD4,1(rSTR2)
+ cmpwi cr1,rWORD3,0
+ bdz L(u3)
+ cmpw rWORD3,rWORD4
+ beq cr1,L(u3)
+ bne L(u3)
+ lbzu rWORD1,1(rSTR1)
+ lbzu rWORD2,1(rSTR2)
+ b L(u1)
+
+L(u3): sub rRTN,rWORD3,rWORD4
+ blr
+L(u4): sub rRTN,rWORD1,rWORD2
+ blr
+L(ux):
+ li rRTN,0
+ blr
+END (strncmp)
+libc_hidden_builtin_def (strncmp)