Blackfin arch: fix some bugs in lib/string.h functions found by our string testing...

 - use ints for the return value rather than char since we actually return
   an int and we dont want it improperly being sign extended during the reload
   http://blackfin.uclinux.org/gf/project/uclinux-dist/tracker/?action=TrackerItemEdit&tracker_item_id=3525

 - if src is shorter than the requested number of copy bytes, we need to null
   pad the rest
   http://blackfin.uclinux.org/gf/project/uclinux-dist/tracker/?action=TrackerItemEdit&tracker_item_id=3524

 - mark these as __volatile__ and add memory to the clobber list so gcc does
   not optimize buffers around on us we may be using

 - rewrite asm code to be readable/maintainable

Signed-off-by: Mike Frysinger <michael.frysinger@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>

diff --git a/include/asm-blackfin/string.h b/include/asm-blackfin/string.h
index 6f1eb7d..e8ada91 100644 (file)
--- a/include/asm-blackfin/string.h
+++ b/include/asm-blackfin/string.h
@@ -9,13 +9,16 @@ extern inline char *strcpy(char *dest, const char *src)
        char *xdest = dest;
        char temp = 0;
 
-       __asm__ __volatile__
-           ("1:\t%2 = B [%1++] (Z);\n\t"
-            "B [%0++] = %2;\n\t"
-            "CC = %2;\n\t"
-        "if cc jump 1b (bp);\n"
-       : "+&a" (dest), "+&a" (src), "=&d" (temp)
-            ::"memory", "CC");
+       __asm__ __volatile__ (
+               "1:"
+               "%2 = B [%1++] (Z);"
+               "B [%0++] = %2;"
+               "CC = %2;"
+               "if cc jump 1b (bp);"
+               : "+&a" (dest), "+&a" (src), "=&d" (temp)
+               :
+               : "memory", "CC");
+
        return xdest;
 }
 
@@ -28,37 +31,56 @@ extern inline char *strncpy(char *dest, const char *src, size_t n)
        if (n == 0)
                return xdest;
 
-       __asm__ __volatile__
-           ("1:\t%3 = B [%1++] (Z);\n\t"
-            "B [%0++] = %3;\n\t"
-            "CC = %3;\n\t"
-            "if ! cc jump 2f;\n\t"
-            "%2 += -1;\n\t"
-            "CC = %2 == 0;\n\t"
-            "if ! cc jump 1b (bp);\n"
-        "2:\n"
-       : "+&a" (dest), "+&a" (src), "+&da" (n), "=&d" (temp)
-            ::"memory", "CC");
+       __asm__ __volatile__ (
+               "1:"
+               "%3 = B [%1++] (Z);"
+               "B [%0++] = %3;"
+               "CC = %3;"
+               "if ! cc jump 2f;"
+               "%2 += -1;"
+               "CC = %2 == 0;"
+               "if ! cc jump 1b (bp);"
+               "jump 4f;"
+               "2:"
+               /* if src is shorter than n, we need to null pad bytes now */
+               "%3 = 0;"
+               "3:"
+               "%2 += -1;"
+               "CC = %2 == 0;"
+               "if cc jump 4f;"
+               "B [%0++] = %3;"
+               "jump 3b;"
+               "4:"
+               : "+&a" (dest), "+&a" (src), "+&da" (n), "=&d" (temp)
+               :
+               : "memory", "CC");
+
        return xdest;
 }
 
 #define __HAVE_ARCH_STRCMP
 extern inline int strcmp(const char *cs, const char *ct)
 {
-       char __res1, __res2;
-
-       __asm__
-       ("1:\t%2 = B[%0++] (Z);\n\t" /* get *cs */
-               "%3 = B[%1++] (Z);\n\t" /* get *ct */
-               "CC = %2 == %3;\n\t"    /* compare a byte */
-               "if ! cc jump 2f;\n\t"  /* not equal, break out */
-               "CC = %2;\n\t"  /* at end of cs? */
-               "if cc jump 1b (bp);\n\t"       /* no, keep going */
-               "jump.s 3f;\n"  /* strings are equal */
-               "2:\t%2 = %2 - %3;\n"   /* *cs - *ct */
-        "3:\n"
-       : "+&a" (cs), "+&a" (ct), "=&d" (__res1), "=&d" (__res2)
-      : :      "CC");
+       /* need to use int's here so the char's in the assembly don't get
+        * sign extended incorrectly when we don't want them to be
+        */
+       int __res1, __res2;
+
+       __asm__ __volatile__ (
+               "1:"
+               "%2 = B[%0++] (Z);"      /* get *cs */
+               "%3 = B[%1++] (Z);"      /* get *ct */
+               "CC = %2 == %3;"         /* compare a byte */
+               "if ! cc jump 2f;"       /* not equal, break out */
+               "CC = %2;"               /* at end of cs? */
+               "if cc jump 1b (bp);"    /* no, keep going */
+               "jump.s 3f;"             /* strings are equal */
+               "2:"
+               "%2 = %2 - %3;"          /* *cs - *ct */
+               "3:"
+               : "+&a" (cs), "+&a" (ct), "=&d" (__res1), "=&d" (__res2)
+               :
+               : "memory", "CC");
 
        return __res1;
 }
@@ -66,26 +88,35 @@ extern inline int strcmp(const char *cs, const char *ct)
 #define __HAVE_ARCH_STRNCMP
 extern inline int strncmp(const char *cs, const char *ct, size_t count)
 {
-       char __res1, __res2;
+       /* need to use int's here so the char's in the assembly don't get
+        * sign extended incorrectly when we don't want them to be
+        */
+       int __res1, __res2;
 
        if (!count)
                return 0;
-       __asm__
-       ("1:\t%3 = B[%0++] (Z);\n\t"        /* get *cs */
-               "%4 = B[%1++] (Z);\n\t" /* get *ct */
-               "CC = %3 == %4;\n\t"    /* compare a byte */
-               "if ! cc jump 3f;\n\t"  /* not equal, break out */
-               "CC = %3;\n\t"  /* at end of cs? */
-               "if ! cc jump 4f;\n\t"  /* yes, all done */
-               "%2 += -1;\n\t" /* no, adjust count */
-       "CC = %2 == 0;\n\t"
-        "if ! cc jump 1b;\n"                 /* more to do, keep going */
-               "2:\t%3 = 0;\n\t"       /* strings are equal */
-        "jump.s    4f;\n"
-        "3:\t%3 = %3 - %4;\n"          /* *cs - *ct */
-        "4:"
-       : "+&a" (cs), "+&a" (ct), "+&da" (count), "=&d" (__res1), "=&d" (__res2)
-      : :      "CC");
+
+       __asm__ __volatile__ (
+               "1:"
+               "%3 = B[%0++] (Z);"      /* get *cs */
+               "%4 = B[%1++] (Z);"      /* get *ct */
+               "CC = %3 == %4;"         /* compare a byte */
+               "if ! cc jump 3f;"       /* not equal, break out */
+               "CC = %3;"               /* at end of cs? */
+               "if ! cc jump 4f;"       /* yes, all done */
+               "%2 += -1;"              /* no, adjust count */
+               "CC = %2 == 0;"
+               "if ! cc jump 1b;"       /* more to do, keep going */
+               "2:"
+               "%3 = 0;"                /* strings are equal */
+               "jump.s 4f;"
+               "3:"
+               "%3 = %3 - %4;"          /* *cs - *ct */
+               "4:"
+               : "+&a" (cs), "+&a" (ct), "+&da" (count), "=&d" (__res1), "=&d" (__res2)
+               :
+               : "memory", "CC");
+
        return __res1;
 }