/* Copies the source block of memory to the destination block of memory while
* switching the endianness of .v64 and .n64 images to the .z64 format, which
* is native to the Nintendo 64. The data extraction routines and MD5 hashing
* function may only act on the .z64 big-endian format.
*
* IN: src: The source block of memory. This must be a valid Nintendo 64 ROM
* image of 'len' bytes.
* len: The length of the source and destination, in bytes.
* OUT: dst: The destination block of memory. This must be a valid buffer for
* at least 'len' bytes.
* imagetype: A pointer to a byte that gets updated with the value of
* V64IMAGE, N64IMAGE or Z64IMAGE according to the format of
* the source block. The value is undefined if 'src' does not
* represent a valid Nintendo 64 ROM image.
*/
static void swap_copy_rom(void* dst, const void* src, size_t len, unsigned char* imagetype)
{
if (memcmp(src, V64_SIGNATURE, sizeof(V64_SIGNATURE)) == 0)
{
size_t i;
const uint16_t* src16 = (const uint16_t*) src;
uint16_t* dst16 = (uint16_t*) dst;
*imagetype = V64IMAGE;
/* .v64 images have byte-swapped half-words (16-bit). */
for (i = 0; i < len; i += 2)
{
*dst16++ = m64p_swap16(*src16++);
}
}
else if (memcmp(src, N64_SIGNATURE, sizeof(N64_SIGNATURE)) == 0)
{
size_t i;
const uint32_t* src32 = (const uint32_t*) src;
uint32_t* dst32 = (uint32_t*) dst;
*imagetype = N64IMAGE;
/* .n64 images have byte-swapped words (32-bit). */
for (i = 0; i < len; i += 4)
{
*dst32++ = m64p_swap32(*src32++);
}
}
else {
*imagetype = Z64IMAGE;
memcpy(dst, src, len);
}
}
/**********************
Byte swap utilities
**********************/
void swap_buffer(void *buffer, size_t length, size_t count)
{
size_t i;
if (length == 2)
{
unsigned short *pun = (unsigned short *)buffer;
for (i = 0; i < count; i++)
pun[i] = m64p_swap16(pun[i]);
}
else if (length == 4)
{
unsigned int *pun = (unsigned int *)buffer;
for (i = 0; i < count; i++)
pun[i] = m64p_swap32(pun[i]);
}
else if (length == 8)
{
unsigned long long *pun = (unsigned long long *)buffer;
for (i = 0; i < count; i++)
pun[i] = m64p_swap64(pun[i]);
}
}
