fix to insure that overlapping strings are properly handled

SCCS-vsn: lib/libc/vax/string/bcopy.s 4.4

diff --git a/usr/src/lib/libc/vax/string/bcopy.s b/usr/src/lib/libc/vax/string/bcopy.s
index dea0e1b..ec495e3 100644 (file)
--- a/usr/src/lib/libc/vax/string/bcopy.s
+++ b/usr/src/lib/libc/vax/string/bcopy.s
@@ -1,18 +1,47 @@
-/* @(#)bcopy.s 4.3 %G% */
+/* @(#)bcopy.s 4.4 %G% */

 /* bcopy(from, to, size) */
 
 #include "DEFS.h"
 
 /* bcopy(from, to, size) */
 
 #include "DEFS.h"
 

-ENTRY(bcopy)
+       .globl  _bcopy
+_bcopy:
+       .word   0x0040
+#ifdef PROF
+       .data; 1:; .long 0; .text; moval 1b,r0; jsb mcount
+#endif PROF

        movl    4(ap),r1
        movl    8(ap),r3
        movl    4(ap),r1
        movl    8(ap),r3

-       jbr     2f
+       movl    12(ap),r6
+       cmpl    r1,r3
+       bgtr    2f              # normal forward case
+       blss    3f              # overlapping, must do backwards
+       ret                     # equal, nothing to do

 1:
 1:

-       subl2   r0,12(ap)
+       subl2   r0,r6

        movc3   r0,(r1),(r3)
 2:
        movzwl  $65535,r0
        movc3   r0,(r1),(r3)
 2:
        movzwl  $65535,r0

-       cmpl    12(ap),r0
+       cmpl    r6,r0

        jgtr    1b
        jgtr    1b

-       movc3   12(ap),(r1),(r3)
+       movc3   r6,(r1),(r3)
+       ret
+3:
+       addl2   r6,r1
+       addl2   r6,r3
+       movzwl  $65535,r0
+       jbr     5f
+4:
+       subl2   r0,r6
+       subl2   r0,r1
+       subl2   r0,r3
+       movc3   r0,(r1),(r3)
+       movzwl  $65535,r0
+       subl2   r0,r1
+       subl2   r0,r3
+5:
+       cmpl    r6,r0
+       jgtr    4b
+       subl2   r6,r1
+       subl2   r6,r3
+       movc3   r6,(r1),(r3)

        ret
        ret