/* Optimized version of the standard strncpy() function.
This file is part of the GNU C Library.
- Copyright (C) 2000, 2001 Free Software Foundation, Inc.
- Contributed by Dan Pop <Dan.Pop@cern.ch>.
+ Copyright (C) 2000-2015 Free Software Foundation, Inc.
+ Contributed by Dan Pop <Dan.Pop@cern.ch>
+ and Jakub Jelinek <jakub@redhat.com>.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
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, write to the Free
- Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
- 02111-1307 USA. */
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
/* Return: dest
Inputs:
- in0: dest
- in1: src
- in2: char count
+ in0: dest
+ in1: src
+ in2: len
- If n >= 24, do a memcpy(dest, src, min(strlen(src)+1, n)), followed by a
- memset(dest + strlen(src), 0, n - strlen(src) - 1) if necessary.
-
- Otherwise, copy characters one by one and fill with nulls if necessary. */
+ In this form, it assumes little endian mode.
+ */
#include <sysdep.h>
#undef ret
-#define saved_b0 loc0
-#define saved_pfs loc1
-#define saved_pr loc2
-#define saved_lc loc3
-#define tmp loc4
-#define len loc5
+#define saved_lc r15
+#define saved_pr r16
+#define thresh r17
+#define dest r18
+#define dest2 r19
+#define src r20
+#define len r21
+#define asrc r22
+#define tmp r23
+#define pos r24
+#define w0 r25
+#define w1 r26
+#define c r27
+#define sh2 r28
+#define sh1 r29
+#define loopcnt r30
+#define value r31
-#define dest in0
-#define src in1
-#define n in2
+ENTRY(strncpy)
+ .prologue
+ alloc r2 = ar.pfs, 3, 0, 29, 32
-#define rc ret0
+#define MEMLAT 2
+ .rotr r[MEMLAT + 2]
+ .rotp p[MEMLAT + 1]
-ENTRY(strncpy)
- .prologue ASM_UNW_PRLG_RP|ASM_UNW_PRLG_PFS, ASM_UNW_PRLG_GRSAVE(3)
- alloc saved_pfs = ar.pfs, 3, 6, 3, 0
- mov saved_b0 = b0
+ mov ret0 = in0 // return value = dest
.save pr, saved_pr
- mov saved_pr = pr
+ mov saved_pr = pr // save the predicate registers
.save ar.lc, saved_lc
- mov saved_lc = ar.lc
+ mov saved_lc = ar.lc // save the loop counter
+ mov ar.ec = 0 // ec is not guaranteed to
+ // be zero upon function entry
.body
- cmp.gtu p6, p0 = 24, n
-(p6) br.cond.spnt .cpyfew
- mov out0 = src
- mov tmp = gp ;;
- br.call.sptk.many b0 = strlen# ;; // rc = strlen(src);
- add len = 1, rc // include the null in len
- mov gp = tmp
- mov out0 = dest ;;
- cmp.ltu p4, p5 = len, n
- mov out1 = src ;;
-(p4) mov out2 = len
-(p5) mov out2 = n
- br.call.sptk.many b0 = memcpy# ;; // memcpy(dest, src, min(len, n));
- mov gp = tmp
-(p4) add out0 = dest, len
-(p4) mov out1 = r0
-(p4) sub out2 = n, len
-(p4) br.call.sptk.many b0 = memset# ;; // fill the rest with nulls
-(p4) mov gp = tmp
- mov rc = dest
- mov b0 = saved_b0
- mov ar.pfs = saved_pfs
- mov pr = saved_pr, -1
- br.ret.sptk.many b0
-.cpyfew:
- mov rc = dest
- cmp.eq p6, p0 = n, r0
- adds n = -1, n
-(p6) br.cond.spnt .restore_and_exit ;; // do nothing if n == 0
- mov ar.lc = n
- cmp.eq p6, p0 = r0, r0 ;; // set p6
-.loop:
-(p6) ld1 tmp = [src],1
+ cmp.geu p6, p5 = 24, in2
+(p6) br.cond.spnt .short_len
+ sub tmp = r0, in0 ;; // tmp = -dest
+ mov len = in2 // len
+ mov dest = in0 // dest
+ mov src = in1 // src
+ and tmp = 7, tmp ;; // loopcnt = -dest % 8
+ cmp.eq p6, p7 = tmp, r0
+ adds loopcnt = -1, tmp // --loopcnt
+(p6) br.cond.sptk .dest_aligned ;;
+ sub len = len, tmp // len -= -dest % 8
+ mov ar.lc = loopcnt
+.l1: // copy -dest % 8 bytes
+(p5) ld1 c = [src], 1 // c = *src++
;;
- st1 [dest] = tmp, 1
-(p6) cmp.ne p6, p0 = tmp, r0 // clear p6 after encountering the
- br.cloop.dptk .loop ;; // null character in src
+ st1 [dest] = c, 1 // *dest++ = c
+ cmp.ne p5, p7 = c, r0
+ br.cloop.dptk .l1 ;;
+(p7) br.cond.dpnt .found0_align
+
+.dest_aligned: // p7 should be cleared here
+ shr.u c = len, 3 // c = len / 8
+ and sh1 = 7, src // sh1 = src % 8
+ and asrc = -8, src ;; // asrc = src & -OPSIZ -- align src
+ adds c = (MEMLAT-1), c // c = (len / 8) + MEMLAT - 1
+ sub thresh = 8, sh1
+ mov pr.rot = 1 << 16 // set rotating predicates
+ shl sh1 = sh1, 3 ;; // sh1 = 8 * (src % 8)
+ mov ar.lc = c // "infinite" loop
+ sub sh2 = 64, sh1 // sh2 = 64 - sh1
+ cmp.eq p6, p0 = sh1, r0 // is the src aligned?
+(p6) br.cond.sptk .src_aligned
+ adds c = -(MEMLAT-1), c ;; // c = (len / 8)
+ ld8 r[1] = [asrc],8
+ mov ar.lc = c ;;
+
+ .align 32
+.l2:
+(p6) st8 [dest] = value, 8 // store val to dest
+ ld8.s r[0] = [asrc], 8
+ shr.u value = r[1], sh1 ;; // value = w0 >> sh1
+ czx1.r pos = value ;; // do we have an "early" zero
+ cmp.lt p7, p0 = pos, thresh // in w0 >> sh1?
+ adds len = -8, len // len -= 8
+(p7) br.cond.dpnt .nonalign_found0
+ chk.s r[0], .recovery2 // it is safe to do that only
+.back2: // after the previous test
+ shl tmp = r[0], sh2 // tmp = w1 << sh2
+ ;;
+ or value = value, tmp ;; // value |= tmp
+ czx1.r pos = value ;;
+ cmp.ne p7, p6 = 8, pos
+(p7) br.cond.dpnt .nonalign_found0
+ br.ctop.dptk .l2 ;;
+ adds len = 8, len
+ br.cond.sptk .not_found0 ;;
+.nonalign_found0:
+ cmp.gtu p6, p0 = -8, len
+(p6) br.cond.dptk .found0
+ adds len = 8, len
+ br.cond.sptk .not_found0 ;;
+
+ .align 32
+.src_aligned:
+.l3:
+(p[0]) ld8.s r[0] = [src], 8
+(p[MEMLAT]) chk.s r[MEMLAT], .recovery3
+.back3:
+(p[MEMLAT]) mov value = r[MEMLAT]
+(p[MEMLAT]) czx1.r pos = r[MEMLAT] ;;
+(p[MEMLAT]) cmp.ne p7, p0 = 8, pos
+(p[MEMLAT]) adds len = -8, len // len -= 8
+(p7) br.cond.dpnt .found0
+(p[MEMLAT]) st8 [dest] = r[MEMLAT], 8
+ br.ctop.dptk .l3 ;;
+
+ chk.s r[MEMLAT-1], .recovery4
+.back4:
+ mov value = r[MEMLAT-1]
+
+.not_found0:
+ cmp.eq p5, p6 = len, r0
+ adds len = -1, len
+(p5) br.cond.dptk .restore_and_exit ;;
+ mov ar.lc = len
+.l4:
+(p6) extr.u c = value, 0, 8 // c = value & 0xff
+(p6) shr.u value = value, 8 ;;
+ st1 [dest] = c, 1
+ cmp.ne p6, p0 = c, r0
+ br.cloop.dptk .l4
+ br.cond.sptk .restore_and_exit
+
+.found0_align:
+ mov pos = 0
+ adds len = -8, len
+ mov value = 0 ;;
+.found0:
+ shl tmp = pos, 3
+ shr.u loopcnt = len, 4 // loopcnt = len / 16
+ mov c = -1 ;;
+ cmp.eq p6, p0 = loopcnt, r0
+ adds loopcnt = -1, loopcnt
+ shl c = c, tmp ;;
+ and len = 0xf, len
+ andcm value = value, c
+ mov ar.lc = loopcnt ;;
+ cmp.le p7, p0 = 8, len
+ adds dest2 = 16, dest
+ st8 [dest] = value, 8
+ and len = 0x7, len
+(p6) br.cond.dpnt .l6 ;;
+.l5:
+ st8 [dest] = r0, 16
+ st8 [dest2] = r0, 16
+ br.cloop.dptk .l5 ;;
+.l6:
+(p7) st8 [dest] = r0, 8
+ cmp.eq p5, p0 = len, r0
+ adds len = -1, len
+(p5) br.cond.dptk .restore_and_exit ;;
+ mov ar.lc = len ;;
+.l7:
+ st1 [dest] = r0, 1
+ br.cloop.dptk .l7 ;;
.restore_and_exit:
- mov ar.lc = saved_lc
- mov ar.pfs = saved_pfs
+ mov ar.lc = saved_lc // restore the loop counter
+ mov pr = saved_pr, -1 // restore the predicate registers
+ br.ret.sptk.many b0
+
+.short_len:
+ cmp.eq p5, p0 = in2, r0
+ adds loopcnt = -1, in2
+(p5) br.cond.spnt .restore_and_exit ;;
+ mov ar.lc = loopcnt // p6 should be set when we get here
+.l8:
+(p6) ld1 c = [in1], 1 // c = *src++
+ ;;
+ st1 [in0] = c, 1 // *dest++ = c
+(p6) cmp.ne p6, p0 = c, r0
+ br.cloop.dptk .l8
+ ;;
+ mov ar.lc = saved_lc // restore the loop counter
+ mov pr = saved_pr, -1 // restore the predicate registers
br.ret.sptk.many b0
+.recovery2:
+ add c = 8, len
+ add tmp = -8, asrc ;;
+ cmp.gtu p8, p5 = c, thresh ;;
+(p8) ld8 r[0] = [tmp]
+(p5) mov r[0] = r0
+ br.cond.sptk .back2
+.recovery3:
+ add tmp = -(MEMLAT + 1) * 8, src ;;
+ ld8 r[MEMLAT] = [tmp]
+ br.cond.sptk .back3
+.recovery4:
+ cmp.eq p5, p6 = len, r0
+ add tmp = -MEMLAT * 8, src ;;
+(p6) ld8 r[MEMLAT - 1] = [tmp]
+(p5) mov r[MEMLAT - 1] = r0
+ br.cond.sptk .back4
END(strncpy)
+libc_hidden_builtin_def (strncpy)
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