buffering

git-svn-id: file:///home/notaz/opt/svn/PicoDrive@67 be3aeb3a-fb24-0410-a615-afba39da0efa

diff --git a/Pico/cd/buffering.c b/Pico/cd/buffering.c
new file mode 100644 (file)
index 0000000..5afc6e8
--- /dev/null
+++ b/Pico/cd/buffering.c
@@ -0,0 +1,112 @@
+#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;
+}
+