| /* |
| FUNCTION |
| <<memset>>---set an area of memory, optimized for the MIPS processors |
| |
| INDEX |
| memset |
| |
| ANSI_SYNOPSIS |
| #include <string.h> |
| void *memset(const void *<[dst]>, int <[c]>, size_t <[length]>); |
| |
| TRAD_SYNOPSIS |
| #include <string.h> |
| void *memset(<[dst]>, <[c]>, <[length]>) |
| void *<[dst]>; |
| int <[c]>; |
| size_t <[length]>; |
| |
| DESCRIPTION |
| This function converts the argument <[c]> into an unsigned |
| char and fills the first <[length]> characters of the array |
| pointed to by <[dst]> to the value. |
| |
| RETURNS |
| <<memset>> returns the value of <[m]>. |
| |
| PORTABILITY |
| <<memset>> is ANSI C. |
| |
| <<memset>> requires no supporting OS subroutines. |
| |
| QUICKREF |
| memset ansi pure |
| */ |
| |
| #include <string.h> |
| |
| #ifdef __mips64 |
| #define wordtype long long |
| #else |
| #define wordtype long |
| #endif |
| |
| #define LBLOCKSIZE (sizeof(wordtype)) |
| #define UNALIGNED(X) ((long)(X) & (LBLOCKSIZE - 1)) |
| #define TOO_SMALL(LEN) ((LEN) < LBLOCKSIZE * 4) |
| |
| _PTR |
| _DEFUN (memset, (m, c, n), |
| _PTR m _AND |
| int c _AND |
| size_t n) |
| { |
| #if defined(PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__) || defined(__mips16) |
| char *s = (char *) m; |
| |
| while (n-- != 0) |
| { |
| *s++ = (char) c; |
| } |
| |
| return m; |
| #else |
| char *s = (char *) m; |
| int i; |
| unsigned wordtype buffer; |
| unsigned wordtype *aligned_addr; |
| unsigned short *short_addr; |
| size_t iter; |
| |
| if (!TOO_SMALL (n)) |
| { |
| int unaligned = UNALIGNED (s); |
| |
| /* We know that N is >= LBLOCKSIZE so we can just word |
| align the S without having to check the length. */ |
| |
| if (unaligned) |
| { |
| while (unaligned++ < LBLOCKSIZE) |
| *s++ = (char)c, n--; |
| } |
| |
| /* S is now word-aligned so we can process the remainder |
| in word sized chunks except for a few (< LBLOCKSIZE) |
| bytes which might be left over at the end. */ |
| |
| aligned_addr = (unsigned wordtype *)s; |
| |
| /* Store C into each char sized location in BUFFER so that |
| we can set large blocks quickly. */ |
| c &= 0xff; |
| buffer = c; |
| if (buffer != 0) |
| { |
| if (LBLOCKSIZE == 4) |
| { |
| buffer |= (buffer << 8); |
| buffer |= (buffer << 16); |
| } |
| else if (LBLOCKSIZE == 8) |
| { |
| buffer |= (buffer << 8); |
| buffer |= (buffer << 16); |
| buffer |= ((buffer << 31) << 1); |
| } |
| else |
| { |
| for (i = 1; i < LBLOCKSIZE; i++) |
| buffer = (buffer << 8) | c; |
| } |
| } |
| |
| iter = n / (2*LBLOCKSIZE); |
| n = n % (2*LBLOCKSIZE); |
| while (iter > 0) |
| { |
| aligned_addr[0] = buffer; |
| aligned_addr[1] = buffer; |
| aligned_addr += 2; |
| iter--; |
| } |
| |
| if (n >= LBLOCKSIZE) |
| { |
| *aligned_addr++ = buffer; |
| n -= LBLOCKSIZE; |
| } |
| |
| /* Pick up the remainder with a bytewise loop. */ |
| s = (char*)aligned_addr; |
| } |
| |
| while (n > 0) |
| { |
| *s++ = (char)c; |
| n--; |
| } |
| |
| return m; |
| #endif /* not PREFER_SIZE_OVER_SPEED */ |
| } |