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Calculate disk reverse translate table once at CTOR time

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This commit is contained in:
Aaron Culliney 2015-10-11 13:21:45 -07:00
parent ddd479f271
commit b8a3521ee5
1 changed files with 13 additions and 13 deletions
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26
src/disk.c
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@ -33,7 +33,7 @@ static int stepper_phases = 0; // state bits for stepper magnet phases 0-3
static int skew_table_6_po[16] = { 0x00,0x08,0x01,0x09,0x02,0x0A,0x03,0x0B, 0x04,0x0C,0x05,0x0D,0x06,0x0E,0x07,0x0F }; // ProDOS order
static int skew_table_6_do[16] = { 0x00,0x07,0x0E,0x06,0x0D,0x05,0x0C,0x04, 0x0B,0x03,0x0A,0x02,0x09,0x01,0x08,0x0F }; // DOS order
static int translate_table_6[0x40] = {
static uint8_t translate_table_6[0x40] = {
0x96, 0x97, 0x9a, 0x9b, 0x9d, 0x9e, 0x9f, 0xa6,
0xa7, 0xab, 0xac, 0xad, 0xae, 0xaf, 0xb2, 0xb3,
0xb4, 0xb5, 0xb6, 0xb7, 0xb9, 0xba, 0xbb, 0xbc,
@ -70,6 +70,17 @@ static int translate_table_6[0x40] = {
*/
};
static uint8_t rev_translate_table_6[0x80] = { 0 };
__attribute__((constructor(CTOR_PRIORITY_LATE)))
static void _initialize_reverse_translate(void) {
unsigned int loop = 0;
while (loop < 0x40) {
rev_translate_table_6[translate_table_6[loop]-0x80] = loop << 2;
loop++;
}
}
static void cut_gz(char *name) {
char *p = name + strlen(name) - 1;
p--;
@ -174,22 +185,11 @@ static void denibblize_sector(const uint8_t *src, uint8_t *out) {
uint8_t work_buf[NUM_SIXBIT_NIBS+1];
uint8_t *dsk = work_buf;
static uint8_t denib[0x80] = { 0 };
static bool tablegenerated = false;
if (!tablegenerated) {
unsigned int loop = 0;
while (loop < 0x40) {
denib[translate_table_6[loop]-0x80] = loop << 2;
loop++;
}
tablegenerated = true;
}
// Convert disk bytes into 6-bit bytes
{
unsigned int loop = NUM_SIXBIT_NIBS+1;
while (loop--) {
*(dsk++) = denib[*(src++) & 0x7F];
*(dsk++) = rev_translate_table_6[*(src++) & 0x7F];
}
}