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-rw-r--r--src/lib/string.C144
1 files changed, 144 insertions, 0 deletions
diff --git a/src/lib/string.C b/src/lib/string.C
new file mode 100644
index 000000000..0444a19bc
--- /dev/null
+++ b/src/lib/string.C
@@ -0,0 +1,144 @@
+#include <string.h>
+
+extern "C" void *memset(void *vdest, int64_t ch, size_t len)
+{
+ // TODO: align to an 8-byte boundary
+ // Loop, storing 8 bytes every 3 instructions
+ long *ldest = reinterpret_cast<long *>(vdest);
+ if (len >= sizeof(long))
+ {
+ long lch = ch & 0xFF;
+ lch |= lch<<8;
+ lch |= lch<<16;
+ lch |= lch<<32;
+ size_t len8 = len / sizeof(long);
+ size_t i = len8;
+ do
+ {
+ ldest[--i] = lch;
+ }
+ while( i > 0 );
+ ldest += len8;
+ len -= len8 * sizeof(long);
+ }
+
+ // Loop, storing 1 byte every 3 instructions
+ char *cdest = reinterpret_cast<char *>(ldest);
+ while (len >= sizeof(char))
+ {
+ *cdest++ = ch;
+ len -= sizeof(char);
+ }
+
+ return vdest;
+}
+
+extern "C" void bzero(void *vdest, size_t len)
+{
+ memset(vdest, 0, len);
+}
+
+extern "C" void *memcpy(void *vdest, const void *vsrc, size_t len)
+{
+ // TODO: align to an 8-byte boundary?
+
+ // Loop, copying 8 bytes every 5 instructions (TODO: 8/4 should be possible)
+ long *ldest = reinterpret_cast<long *>(vdest);
+ const long *lsrc = reinterpret_cast<const long *>(vsrc);
+
+ while (len >= sizeof(long))
+ {
+ *ldest++ = *lsrc++;
+ len -= sizeof(long);
+ }
+
+ // Loop, copying 1 byte every 4 instructions
+ char *cdest = reinterpret_cast<char *>(ldest);
+ const char *csrc = reinterpret_cast<const char *>(lsrc);
+ for (size_t i = 0; i < len; ++i)
+ {
+ cdest[i] = csrc[i];
+ }
+
+ return vdest;
+}
+
+extern "C" void *memmove(void *vdest, const void *vsrc, size_t len)
+{
+ // Copy first-to-last
+ if (vdest <= vsrc)
+ {
+ return memcpy(vdest,vsrc,len);
+ }
+
+ // Copy last-to-first (TO_DO: optimize)
+ char *dest = reinterpret_cast<char *>(vdest);
+ const char *src = reinterpret_cast<const char *>(vsrc);
+ for (size_t i = len; i > 0;)
+ {
+ --i;
+ dest[i] = src[i];
+ }
+
+ return vdest;
+}
+
+extern "C" int64_t memcmp(const void *p1, const void *p2, size_t len)
+{
+ const char *c1 = reinterpret_cast<const char *>(p1);
+ const char *c2 = reinterpret_cast<const char *>(p2);
+
+ for (size_t i = 0; i < len; ++i)
+ {
+ long n = static_cast<long>(c1[i]) - static_cast<long>(c2[i]);
+ if (n != 0)
+ {
+ return n;
+ }
+ }
+
+ return 0;
+}
+
+extern "C" char* strcpy(char* d, const char* s)
+{
+ char* d1 = d;
+
+ do
+ {
+ *d1 = *s;
+ if (*s == '\0') return d;
+ d1++; s++;
+ } while(1);
+}
+
+extern "C" int strcmp(const char* a, const char* b)
+{
+ while((*a != '\0') && (*b != '\0'))
+ {
+ if (*a == *b)
+ {
+ a++; b++;
+ }
+ else
+ {
+ return (*a > *b) ? 1 : -1;
+ }
+ }
+ if (*a == *b)
+ return 0;
+ if (*a == '\0')
+ return -1;
+ else
+ return 1;
+}
+
+extern "C" size_t strlen(const char* a)
+{
+ size_t length = 0;
+ while(*a++)
+ {
+ length++;
+ }
+ return length;
+}
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