diff options
Diffstat (limited to 'arch/blackfin/lib/strncpy.S')
| -rw-r--r-- | arch/blackfin/lib/strncpy.S | 59 |
1 files changed, 46 insertions, 13 deletions
diff --git a/arch/blackfin/lib/strncpy.S b/arch/blackfin/lib/strncpy.S index 39fbbe6..f3931d5 100644 --- a/arch/blackfin/lib/strncpy.S +++ b/arch/blackfin/lib/strncpy.S @@ -5,12 +5,14 @@ */ #include <linux/linkage.h> +#include <asm/context.S> /* void *strncpy(char *dest, const char *src, size_t n); * R0 = address (dest) * R1 = address (src) * R2 = size - * Returns a pointer to the destination string dest + * Returns a pointer (R0) to the destination string dest + * we do this by not changing R0 */ #ifdef CONFIG_STRNCPY_L1 @@ -24,29 +26,60 @@ ENTRY(_strncpy) CC = R2 == 0; if CC JUMP 4f; + + P2 = R2 ; /* size */ P0 = R0 ; /* dst*/ P1 = R1 ; /* src*/ + LSETUP (1f, 2f) LC0 = P2; 1: R1 = B [P1++] (Z); B [P0++] = R1; - CC = R1; - if ! cc jump 2f; - R2 += -1; - CC = R2 == 0; - if ! cc jump 1b (bp); - jump 4f; + CC = R1 == 0; 2: - /* if src is shorter than n, we need to null pad bytes in dest */ - R1 = 0; + if CC jump 3f; + + RTS; + + /* if src is shorter than n, we need to null pad bytes in dest + * but, we can get here when the last byte is zero, and we don't + * want to copy an extra byte at the end, so we need to check + */ 3: + R2 = LC0; + CC = R2 + if ! CC jump 6f; + + /* if the required null padded portion is small, do it here, rather than + * handling the overhead of memset (which is OK when things are big). + */ + R3 = 0x20; + CC = R2 < R3; + IF CC jump 4f; + R2 += -1; - CC = R2 == 0; - if cc jump 4f; - B [P0++] = R1; - jump 3b; + + /* Set things up for memset + * R0 = address + * R1 = filler byte (this case it's zero, set above) + * R2 = count (set above) + */ + + I1 = R0; + R0 = RETS; + I0 = R0; + R0 = P0; + pseudo_long_call _memset, p0; + R0 = I0; + RETS = R0; + R0 = I1; + RTS; 4: + LSETUP(5f, 5f) LC0; +5: + B [P0++] = R1; +6: RTS; ENDPROC(_strncpy) |
