repo2/firmware_legacy/atx_eclaire.c
| 864 | markw | #include "atx_eclaire.h"
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#include "atx.h"
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#include "regs.h"
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struct SimpleFile * gAtxFile;
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u16 last_angle_returned; // extern so we can display it on the screen
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extern unsigned char atari_sector_buffer[256];
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void longbyteswap(u32 * x);
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void byteswap(u16 * x);
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void byteSwapAtxFileHeader(struct atxFileHeader * header)
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{
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// only swap the used entries
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byteswap(&header->version);
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byteswap(&header->minVersion);
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longbyteswap(&header->startData);
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}
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void byteSwapAtxTrackHeader(struct atxTrackHeader * header)
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{
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// only swap the used entries
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longbyteswap(&header->size); // used
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byteswap(&header->sectorCount); // used
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longbyteswap(&header->headerSize); // used
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}
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void byteSwapAtxSectorListHeader(struct atxSectorListHeader * header)
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{
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longbyteswap(&header->next);
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}
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void byteSwapAtxSectorHeader(struct atxSectorHeader * header)
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{
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byteswap(&header->timev);
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longbyteswap(&header->data);
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}
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void byteSwapAtxTrackChunk(struct atxTrackChunk *header)
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{
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byteswap(&header->data);
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longbyteswap(&header->size);
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}
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void waitForAngularPosition(u16 pos)
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{
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int where = getCurrentHeadPosition();
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int diff = pos-where;
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if (diff < 0)
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{
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diff = 26042+diff;
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}
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*zpu_pause = diff<<3;
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/* // if the position is less than the current timer, we need to wait for a rollover
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// to occur
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if (pos < TCNT1 / 2) {
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TIFR1 |= _BV(OCF1A);
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while (!(TIFR1 & _BV(OCF1A)));
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}
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// wait for the timer to reach the target position
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while (TCNT1 / 2 < pos);*/
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}
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u16 getCurrentHeadPosition() {
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// TCNT1 is a variable driven by an Atmel timer that ticks every 4 microseconds. A full
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// rotation of the disk is represented in an ATX file by an angular positional value
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// between 1-26042 (or 8 microseconds based on 288 rpms). So, TCNT1 / 2 always gives the
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// current angular position of the drive head on the track any given time assuming the
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// disk is spinning continously.
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//return TCNT1 / 2;
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int res = *zpu_timer2;
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res = (res >> 3)+1;
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return res;
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}
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int faccess_offset(int type, int offset, int bytes)
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{
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int read = 0;
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*zpu_timer2_threshold = 208335;
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file_seek(gAtxFile,offset);
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file_read(gAtxFile,&atari_sector_buffer[0],bytes,&read);
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return bytes==read;
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}
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int rand()
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{
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return *zpu_rand;
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}
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extern void byteswap(WORD * inw);
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void longbyteswap(u32 * inl)
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{
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#ifndef LITTLE_ENDIAN
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unsigned char * in = (unsigned char *)inl;
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unsigned char temp0 = in[0];
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unsigned char temp1 = in[1];
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in[0] = in[3];
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in[1] = in[2];
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in[2] = temp1;
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in[3] = temp0;
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#endif
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}
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