Apple-2-Tools
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dsk2woz
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Standardises various minor type decisions and slightly optimises.

This commit is contained in:
Thomas Harte 2018-06-06 19:59:08 -04:00
parent c9156b3ebe
commit b1ee05a3cb
1 changed files with 40 additions and 38 deletions
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78
dsk2woz.c
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@ -50,6 +50,8 @@ int main(int argc, char *argv[]) {
// calculated later.
const size_t woz_image_size = 256 - 12 + 35*6656;
uint8_t woz[woz_image_size];
memset(woz, 0, sizeof(woz));
#define set_int32(location, value) \
woz[location] = (value) & 0xff; \
woz[location+1] = ((value) >> 8) & 0xff; \
@ -79,8 +81,8 @@ int main(int argc, char *argv[]) {
strcpy((char *)&woz[13], creator);
memset(&woz[13 + strlen(creator)], 32 - strlen(creator), ' ');
// Chunk should be padded with 0s to reach 60 bytes in length.
memset(&woz[13 + 32], (8+60) - (13 + 32), 0);
// Chunk should be padded with 0s to reach 60 bytes in length;
// the buffer was memset to 0 at initialisation so that's implicit.
@ -98,12 +100,13 @@ int main(int argc, char *argv[]) {
//
// The remaining quarter-track position maps to nothing, which in
// WOZ is indicated with a value of 255.
// Let's start by filling the entire TMAP with empty tracks.
memset(&woz[76], 0xff, 160);
// Then we will add in the mappings.
for(int c = 0; c < 35; ++c) {
int track_position = 76 + (c << 2);
if (c > 0) woz[track_position - 1] = c;
// Let's start by filling the entire TMAP with empty tracks.
memset(&woz[76], 0xff, 160);
// Then we will add in the mappings.
for(size_t c = 0; c < 35; ++c) {
const size_t track_position = 76 + (c << 2);
if(c > 0) woz[track_position - 1] = c;
woz[track_position] = woz[track_position + 1] = c;
}
@ -119,7 +122,7 @@ int main(int argc, char *argv[]) {
size_t output_pointer = 244;
// Write out all 35 tracks.
for(int c = 0; c < 35; ++c) {
for(size_t c = 0; c < 35; ++c) {
serialise_track(&woz[output_pointer], &dsk[c * 16 * 256], c, is_prodos);
output_pointer += 6656;
}
@ -260,12 +263,13 @@ static size_t write_bit(uint8_t *buffer, size_t position, int value) {
@return The position immediately after the byte.
*/
static size_t write_byte(uint8_t *buffer, size_t position, int value) {
int mask = 0x80;
while(mask) {
position = write_bit(buffer, position, value & mask);
mask >>= 1;
}
return position;
const size_t shift = position & 7;
const size_t byte_position = position >> 3;
buffer[byte_position] |= value >> shift;
if(shift) buffer[byte_position+1] |= value << (8 - shift);
return position + 8;
}
/*!
@ -274,7 +278,7 @@ static size_t write_byte(uint8_t *buffer, size_t position, int value) {
@param buffer The buffer to write into.
@param position The position to write at.
@param value The byte to encode and write.
@return The position immediately after the byte.
@return The position immediately after the encoded byte.
*/
static size_t write_4_and_4(uint8_t *buffer, size_t position, int value) {
position = write_byte(buffer, position, (value >> 1) | 0xaa);
@ -291,9 +295,7 @@ static size_t write_4_and_4(uint8_t *buffer, size_t position, int value) {
*/
static size_t write_sync(uint8_t *buffer, size_t position) {
position = write_byte(buffer, position, 0xff);
position = write_bit(buffer, position, 0);
position = write_bit(buffer, position, 0);
return position;
return position + 2; // Skip two bits, i.e. leave them as 0s.
}
/*!
@ -365,13 +367,13 @@ static void serialise_track(uint8_t *dest, const uint8_t *src, uint8_t track_num
size_t track_position = 0; // This is the track position **in bits**.
memset(dest, 0, 6646);
// Write the gap 1.
for(int c = 0; c < 16; ++c) {
track_position = write_sync(dest, track_position);
}
// Write gap 1.
for(size_t c = 0; c < 16; ++c) {
track_position = write_sync(dest, track_position);
}
// Step through the physical sector.
for(int sector = 0; sector < 16; ++sector) {
for(size_t sector = 0; sector < 16; ++sector) {
/*
Write the sector header.
*/
@ -393,11 +395,11 @@ static void serialise_track(uint8_t *dest, const uint8_t *src, uint8_t track_num
track_position = write_byte(dest, track_position, 0xeb);
// Write the gap 2.
for(int c = 0; c < 7; ++c) {
track_position = write_sync(dest, track_position);
}
// Write gap 2.
for(size_t c = 0; c < 7; ++c) {
track_position = write_sync(dest, track_position);
}
/*
Write the sector body.
*/
@ -422,18 +424,18 @@ static void serialise_track(uint8_t *dest, const uint8_t *src, uint8_t track_num
track_position = write_byte(dest, track_position, 0xaa);
track_position = write_byte(dest, track_position, 0xeb);
// Write the gap 3.
for(int c = 0; c < 16; ++c) {
track_position = write_sync(dest, track_position);
}
}
// Write gap 3.
for(size_t c = 0; c < 16; ++c) {
track_position = write_sync(dest, track_position);
}
}
// Add the track suffix.
dest[6646] = (track_position >> 3) & 0xff;
dest[6647] = (track_position >> 11) & 0xff; // Byte count.
dest[6648] = track_position & 0xff;
dest[6649] = (track_position >> 8) & 0xff; // Bit count.
dest[6650] = dest[6651] = 0x00; // Splice information.
dest[6652] = 0xff;
dest[6653] = 10;
dest[6652] = 0xff;
dest[6653] = 10;
}