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buffering

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git-svn-id: file:///home/notaz/opt/svn/PicoDrive@67 be3aeb3a-fb24-0410-a615-afba39da0efa
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notaz 2007-03-11 23:46:51 +00:00
parent 0a051f558c
commit 8b71d0ebf9
1 changed files with 112 additions and 0 deletions
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112
Pico/cd/buffering.c Normal file
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#include "../PicoInt.h"
//#include <stdlib.h>
int PicoCDBuffers = 0;
static unsigned char *cd_buffer = NULL;
static int prev_lba = 0x80000000;
static int hits, reads;
void PicoCDBufferInit(void)
{
void *tmp;
prev_lba = 0x80000000;
hits = reads = 0;
if (PicoCDBuffers <= 1) {
PicoCDBuffers = 0;
return; /* buffering off */
}
/* try alloc'ing until we succeed */
while (PicoCDBuffers > 0)
{
tmp = realloc(cd_buffer, PicoCDBuffers * 2048);
if (tmp != NULL) break;
PicoCDBuffers >>= 1;
}
if (PicoCDBuffers <= 0) return; /* buffering became off */
cd_buffer = tmp;
}
void PicoCDBufferFree(void)
{
if (cd_buffer) {
free(cd_buffer);
cd_buffer = NULL;
}
if (reads)
printf("CD buffer hits: %i/%i (%i%%)\n", hits, reads, hits * 100 / reads);
}
/* this is a try to fight slow SD access of GP2X */
void PicoCDBufferRead(void *dest, int lba)
{
int is_bin, offs, read_len;
reads++;
is_bin = Pico_mcd->TOC.Tracks[0].ftype == TYPE_BIN;
if (PicoCDBuffers <= 0)
{
/* no buffering */
int where_seek = is_bin ? (lba * 2352 + 16) : (lba << 11);
pm_seek(Pico_mcd->TOC.Tracks[0].F, where_seek, SEEK_SET);
pm_read(dest, 2048, Pico_mcd->TOC.Tracks[0].F);
return;
}
/* hit? */
offs = lba - prev_lba;
if (offs >= 0 && offs < PicoCDBuffers)
{
hits++;
if (offs == 0) dprintf("CD buffer seek to old %i -> %i\n", prev_lba, lba);
memcpy32(dest, (int *)(cd_buffer + offs*2048), 2048/4);
return;
}
if (prev_lba + PicoCDBuffers != lba)
{
int where_seek = is_bin ? (lba * 2352 + 16) : (lba << 11);
dprintf("CD buffer seek %i -> %i\n", prev_lba, lba);
pm_seek(Pico_mcd->TOC.Tracks[0].F, where_seek, SEEK_SET);
}
dprintf("CD buffer miss %i -> %i\n", prev_lba, lba);
if (lba < prev_lba && prev_lba - lba < PicoCDBuffers)
{
dprintf("CD buffer move");
read_len = prev_lba - lba;
memmove(cd_buffer + read_len*2048, cd_buffer, (PicoCDBuffers - read_len)*2048);
}
else
{
read_len = PicoCDBuffers;
}
if (is_bin)
{
int i;
for (i = 0; i < read_len; i++)
{
pm_read(cd_buffer + i*2048, 2048, Pico_mcd->TOC.Tracks[0].F);
pm_seek(Pico_mcd->TOC.Tracks[0].F, 304, SEEK_CUR);
}
}
else
{
pm_read(cd_buffer, read_len*2048, Pico_mcd->TOC.Tracks[0].F);
}
memcpy32(dest, (int *) cd_buffer, 2048/4);
prev_lba = lba;
}