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GBA: Flash erase timing changes

This commit is contained in:
Jeffrey Pfau 2015-06-19 04:25:29 -07:00
parent 833d81ee75
commit 8538e99a08
2 changed files with 9 additions and 1 deletions
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1
CHANGES
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@ -80,6 +80,7 @@ Misc:
- Qt: Make the default fullscreen binding for Windows be Alt-Enter - Qt: Make the default fullscreen binding for Windows be Alt-Enter
- GBA Video: Refactor software renderer into separate files - GBA Video: Refactor software renderer into separate files
- ARM7: Add emulation for Undefined CPU mode - ARM7: Add emulation for Undefined CPU mode
- GBA: More accurate cycle estimation for ROM prefetch and flash save chips
0.2.1: (2015-05-13) 0.2.1: (2015-05-13)
Bugfixes: Bugfixes:

9
src/gba/savedata.c
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@ -14,6 +14,11 @@
#include <errno.h> #include <errno.h>
#include <fcntl.h> #include <fcntl.h>
// Some testing was done here...
// Erase cycles can vary greatly.
// Some games may vary anywhere between about 2000 cycles to up to 30000 cycles. (Observed on a Macronix (09C2) chip).
// Other games vary from very little, with a fairly solid 20500 cycle count. (Observed on a SST (D4BF) chip).
// An average estimation is as follows.
#define FLASH_SETTLE_CYCLES 18000 #define FLASH_SETTLE_CYCLES 18000
static void _flashSwitchBank(struct GBASavedata* savedata, int bank); static void _flashSwitchBank(struct GBASavedata* savedata, int bank);
@ -234,7 +239,9 @@ uint8_t GBASavedataReadFlash(struct GBASavedata* savedata, uint16_t address) {
} }
} }
if (savedata->dust > 0 && (address >> 12) == savedata->settling) { if (savedata->dust > 0 && (address >> 12) == savedata->settling) {
--savedata->dust; // Give some overhead for waitstates and the comparison
// This estimation can probably be improved
savedata->dust -= 10;
return 0x5F; return 0x5F;
} }
return savedata->currentBank[address]; return savedata->currentBank[address];