[7738906] | 1 | /* |
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| 2 | * C library memcpy routine |
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| 3 | * |
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| 4 | * This routine has code to optimize performance on the CPU32+ |
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| 5 | * and another version for other 68k machines. |
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| 6 | * |
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| 7 | * It could be optimized more for machines with MOVE16 instructions. |
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| 8 | * |
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| 9 | * The routine is placed in this source directory to ensure that it |
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| 10 | * is picked up by all applications. |
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| 11 | * |
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| 12 | * W. Eric Norum |
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| 13 | * Saskatchewan Accelerator Laboratory |
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| 14 | * University of Saskatchewan |
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| 15 | * Saskatoon, Saskatchewan, CANADA |
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| 16 | * eric@skatter.usask.ca |
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| 17 | */ |
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| 18 | |
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| 19 | #include <string.h> |
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| 20 | #include <rtems/score/m68k.h> |
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| 21 | |
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| 22 | #if defined(__mcpu32__) |
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| 23 | #define COPYSETUP(n) n-- |
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| 24 | #define COPY(to,from,n,size) \ |
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| 25 | asm volatile ("1:\n" \ |
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| 26 | "\tmove." size " (%0)+,(%1)+\n" \ |
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| 27 | "\tdbf %2,1b\n" \ |
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| 28 | "\tsub.l #0x10000,%2\n" \ |
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| 29 | "\tbpl.b 1b\n" : \ |
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| 30 | "=a" (from), "=a" (to), "=d" (n) :\ |
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| 31 | "0" (from), "1" (to), "2" (n) : \ |
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| 32 | "cc", "memory") |
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| 33 | #else |
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| 34 | #define COPYSETUP(n) |
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| 35 | #define COPY(to,from,n,size) \ |
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| 36 | asm volatile ("1:\n" \ |
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| 37 | "\tmove." size " (%0)+,(%1)+\n" \ |
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| 38 | "\tsubq.l #1,%2\n\tbne.b 1b\n" : \ |
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| 39 | "=a" (from), "=a" (to), "=d" (n) :\ |
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| 40 | "0" (from), "1" (to), "2" (n) : \ |
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| 41 | "cc", "memory") |
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| 42 | #endif |
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| 43 | |
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[3f5480c] | 44 | /* gcc doesn't know that cpu32+ is better than cpu32 :( */ |
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| 45 | #if defined(__mcpu32p__) |
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| 46 | #undef M68k_HAS_MISALIGNED |
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| 47 | #define M68k_HAS_MISALIGNED 1 |
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| 48 | #endif |
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| 49 | |
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[7738906] | 50 | void * |
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| 51 | memcpy(void *s1, const void *s2, size_t n) |
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| 52 | { |
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| 53 | char *p1 = s1; |
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| 54 | const char *p2 = s2; |
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| 55 | |
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| 56 | if (n) { |
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| 57 | if (n < 16) { |
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| 58 | COPYSETUP (n); |
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| 59 | COPY (p1, p2, n, "b"); |
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| 60 | } |
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| 61 | else { |
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| 62 | int nbyte; |
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| 63 | int nl; |
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| 64 | nbyte = (int)p1 & 0x3; |
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| 65 | if (nbyte) { |
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| 66 | nbyte = 4 - nbyte; |
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| 67 | n -= nbyte; |
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| 68 | COPYSETUP (nbyte); |
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| 69 | COPY (p1, p2, nbyte, "b"); |
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| 70 | } |
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| 71 | #if (M68K_HAS_MISALIGNED == 0) |
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| 72 | /* |
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| 73 | * Take care of machines that can't |
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| 74 | * handle misaligned references. |
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| 75 | */ |
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| 76 | if ((int)p2 & 0x1) { |
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| 77 | COPYSETUP (n); |
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| 78 | COPY (p1, p2, n, "b"); |
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| 79 | return s1; |
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| 80 | } |
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| 81 | #endif |
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| 82 | nl = (unsigned int)n >> 2; |
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| 83 | COPYSETUP (nl); |
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| 84 | COPY (p1, p2, nl, "l"); |
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| 85 | nbyte = (int)n & 0x3; |
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| 86 | if (nbyte) { |
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| 87 | COPYSETUP (nbyte); |
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| 88 | COPY (p1, p2, nbyte, "b"); |
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| 89 | } |
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| 90 | } |
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| 91 | } |
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| 92 | return s1; |
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| 93 | } |
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