Skip to content
Permalink
Browse files

libretro: add SIO Control register (GBA)

- emulate SIOCNT reg, which is still needed for some games to trigger IRQ's even in single, non-link mode
- Fixes Digimon Racing (Europe) stuck in intro as reported in libretro docs page https://docs.libretro.com/library/vba_m/#compatibility
- Related PR: libretro/vbam-libretro@f9efb79#diff-385704891f00846c986e9056b5d7c5a5
  • Loading branch information
retro-wertz
retro-wertz committed Jul 23, 2019
1 parent f09a9aa commit 53ce6fb0541954ef13a57fa5776d81c8569fce4c
Showing with 23 additions and 1 deletion.
  1. +23 −1 src/libretro/libretro.cpp
@@ -90,14 +90,19 @@ bool EmuReseted;
int winGbPrinterEnabled;
bool gba_joybus_active = false;

#define UPDATE_REG(address, value) WRITE16LE(((uint16_t*)&ioMem[address]), value)

LinkMode GetLinkMode()
{
return LINK_DISCONNECTED;
}

void StartGPLink(uint16_t value)
{
WRITE16LE(((uint16_t*)&ioMem[COMM_RCNT]), value);
if (!ioMem)
return;

UPDATE_REG(COMM_RCNT, value);
}

void LinkUpdate(int ticks)
@@ -106,6 +111,23 @@ void LinkUpdate(int ticks)

void StartLink(uint16_t siocnt)
{
/* log("'s' siocnt = %04x\n", siocnt); */

if (!ioMem)
return;

if(siocnt & 0x80)
{
siocnt &= 0xff7f;
if(siocnt & 1 && (siocnt & 0x4000))
{
UPDATE_REG(COMM_SIOCNT, 0xFF);
IF |= 0x80;
UPDATE_REG(0x202, IF);
siocnt &= 0x7f7f;
}
}
UPDATE_REG(COMM_SIOCNT, siocnt);
}

void CheckLinkConnection()

0 comments on commit 53ce6fb

Please sign in to comment.
You can’t perform that action at this time.