[src/trunk]: src/common/lib/libc/arch/arm/string Add support for strnlen.

[matt <matt%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/211fd2a97b0d
branches:  trunk
changeset: 784252:211fd2a97b0d
user:      matt <matt%NetBSD.org@localhost>
date:      Wed Jan 23 06:59:55 2013 +0000

description:
Add support for strnlen.

diffstat:

 common/lib/libc/arch/arm/string/strlen_arm.S   |  42 +++++++++++++++++++++++--
 common/lib/libc/arch/arm/string/strlen_naive.S |  19 +++++++++++-
 2 files changed, 56 insertions(+), 5 deletions(-)

diffs (113 lines):

diff -r c2c7a4e5da18 -r 211fd2a97b0d common/lib/libc/arch/arm/string/strlen_arm.S
--- a/common/lib/libc/arch/arm/string/strlen_arm.S      Wed Jan 23 06:53:30 2013 +0000
+++ b/common/lib/libc/arch/arm/string/strlen_arm.S      Wed Jan 23 06:59:55 2013 +0000
@@ -29,7 +29,7 @@
 
 #include <machine/asm.h>
 
-RCSID("$NetBSD: strlen_arm.S,v 1.2 2013/01/09 00:01:07 matt Exp $")
+RCSID("$NetBSD: strlen_arm.S,v 1.3 2013/01/23 06:59:55 matt Exp $")
 
 #ifdef __ARMEL__
 #define        BYTE0   0x000000ff
@@ -43,16 +43,34 @@
 #define        BYTE3   0x000000ff
 #endif
 
+#ifdef STRNLEN
+#define        FUNCNAME        strnlen
+#else
+#define        FUNCNAME        strlen
+#endif
+
        .text
-ENTRY(strlen)
+ENTRY(FUNCNAME)
+#ifdef STRNLEN
+       push    {r4,r5}                 /* save some registers */
+       add     r5, r0, r1              /* get ptr to end of string */
+       mov     r4, r1                  /* save maxlen */
+#endif
        add     ip, r0, #4              /* for the final post-inc */
 1:     tst     r0, #3                  /* test for word alignment */
        beq     .Lpre_main_loop         /*   finally word aligned */
+#ifdef STRNLEN
+       cmp     r0, r5                  /* have we gone too far? */
+       beq     .Lmaxed_out             /*   yes, return maxlen */
+#endif
        ldrb    r3, [r0], #1            /* load a byte */
        teq     r3, #0                  /* is it 0? */
        bne     1b                      /*   no, try next byte */
        sub     ip, ip, #3              /* subtract (4 - the NUL) */
        sub     r0, r0, ip              /* subtract start */
+#ifdef STRNLEN
+       pop     {r4, r5}                /* restore registers */
+#endif
        RET                             /* return */
 .Lpre_main_loop:
 #if defined(_ARM_ARCH_7)
@@ -64,6 +82,10 @@
        orr     r1, r1, r1, lsl #16     /* move to next halfword */
 #endif /* _ARM_ARCH_6 */
 .Lmain_loop:
+#ifdef STRNLEN
+       cmp     r0, r5                  /* gone too far? */
+       bge     .Lmaxed_out             /*   yes, return maxlen */
+#endif
        ldr     r3, [r0], #4            /* load next word */
 #if defined(_ARM_ARCH_6)
        /*
@@ -116,5 +138,17 @@
         * the post-inc.
         */
        sub     r0, r0, ip              /* subtract start to get length */
-       RET
-END(strlen)
+#ifdef STRNLEN
+       cmp     r0, r4                  /* is it larger than maxlen? */
+       movgt   r0, r4                  /*   yes, return maxlen */
+       pop     {r4, r5}                /* restore registers */
+#endif
+       RET                             /* return */
+
+#ifdef STRNLEN
+.Lmaxed_out:
+       mov     r0, r4                  /* return maxlen */
+       pop     {r4, r5}                /* restore registers */
+       RET                             /* return */
+#endif
+END(FUNCNAME)
diff -r c2c7a4e5da18 -r 211fd2a97b0d common/lib/libc/arch/arm/string/strlen_naive.S
--- a/common/lib/libc/arch/arm/string/strlen_naive.S    Wed Jan 23 06:53:30 2013 +0000
+++ b/common/lib/libc/arch/arm/string/strlen_naive.S    Wed Jan 23 06:59:55 2013 +0000
@@ -28,8 +28,24 @@
  */
 #include <machine/asm.h>
 
-RCSID("$NetBSD: strlen_naive.S,v 1.2 2013/01/08 16:58:59 pgoyette Exp $")
+RCSID("$NetBSD: strlen_naive.S,v 1.3 2013/01/23 06:59:55 matt Exp $")
 
+#ifdef STRNLEN
+/* LINTSTUB: size_t strnlen(const char *, size_t) */
+ENTRY(strnlen)
+       add     ip, r0, #1      /* start of src + NUL */
+       add     r2, r0, r1      /* &src[maxlen] */
+1:     cmp     r0, r2          /* is this of string? */
+       beq     2f              /*   yes it is */
+       ldrb    r3, [r0], #1    /* read a byte */
+       teq     r3, #0          /* is it a NUL? */
+       bne     1b              /*   no, get next byte */
+       sub     r0, r0, ip      /* get difference between start and end */
+       RET                     /* return */
+2:     mov     r0, r1          /* get maxlen */
+       RET                     /* return */
+END(strnlen)
+#else /* STRNLEN */
 /* LINTSTUB: size_t strlen(const char *) */
 ENTRY(strlen)
        add     ip, r0, #1      /* start of src + NUL */
@@ -39,3 +55,4 @@
        sub     r0, r0, ip      /* return difference between start and end */
        RET
 END(strlen)
+#endif /* !STRNLEN */