diff options
| -rw-r--r-- | ports/ChangeLog.arm | 3 | ||||
| -rw-r--r-- | ports/sysdeps/arm/armv6t2/memchr.S | 25 |
2 files changed, 26 insertions, 2 deletions
diff --git a/ports/ChangeLog.arm b/ports/ChangeLog.arm index d24a109..2e250f7 100644 --- a/ports/ChangeLog.arm +++ b/ports/ChangeLog.arm @@ -1,5 +1,8 @@ 2013-03-12 Roland McGrath <roland@hack.frob.com> + * sysdeps/arm/armv6t2/memchr.S [NO_THUMB]: + Use .arm rather than .thumb, .thumb_func. Avoid cbz/cnbz instructions. + * sysdeps/arm/armv6t2/memchr.S: Change register allocation so ldrd use is r4,r5 rather than r5,r6; this way ARM mode will allow that ldrd. diff --git a/ports/sysdeps/arm/armv6t2/memchr.S b/ports/sysdeps/arm/armv6t2/memchr.S index e253a66..7f644c3 100644 --- a/ports/sysdeps/arm/armv6t2/memchr.S +++ b/ports/sysdeps/arm/armv6t2/memchr.S @@ -42,10 +42,12 @@ .syntax unified .text +#ifdef NO_THUMB + .arm +#else .thumb - -@ --------------------------------------------------------------------------- .thumb_func +#endif .global memchr .type memchr,%function ENTRY(memchr) @@ -89,14 +91,22 @@ ENTRY(memchr) 15: ldrd r4,r5, [r0],#8 +#ifndef NO_THUMB subs r6, r6, #8 +#endif eor r4,r4, r1 @ Get it so that r4,r5 have 00's where the bytes match the target eor r5,r5, r1 uadd8 r4, r4, r7 @ Parallel add 0xff - sets the GE bits for anything that wasn't 0 sel r4, r3, r7 @ bytes are 00 for none-00 bytes, or ff for 00 bytes - NOTE INVERSION uadd8 r5, r5, r7 @ Parallel add 0xff - sets the GE bits for anything that wasn't 0 sel r5, r4, r7 @ chained....bytes are 00 for none-00 bytes, or ff for 00 bytes - NOTE INVERSION +#ifndef NO_THUMB cbnz r5, 60f +#else + cmp r5, #0 + bne 60f + subs r6, r6, #8 +#endif bne 15b @ (Flags from the subs above) If not run out of bytes then go around again pop {r4,r5,r6,r7} @@ -110,13 +120,24 @@ ENTRY(memchr) and r2,r2,#7 @ Leave the count remaining as the number after the double words have been done 20: +#ifndef NO_THUMB cbz r2, 40f @ 0 length or hit the end already then not found +#else + cmp r2, #0 + beq 40f +#endif 21: @ Post aligned section, or just a short call ldrb r3,[r0],#1 +#ifndef NO_THUMB subs r2,r2,#1 eor r3,r3,r1 @ r3 = 0 if match - doesn't break flags from sub cbz r3, 50f +#else + eors r3, r3, r1 + beq 50f + subs r2, r2, #1 +#endif bne 21b @ on r2 flags 40: |