diff options
Diffstat (limited to 'src/zx81.c')
| -rw-r--r-- | src/zx81.c | 21 |
1 files changed, 12 insertions, 9 deletions
@@ -174,14 +174,14 @@ static void RomPatch(void) static const Z80Byte save[]= { 0xed, 0xf0, /* ED F0 illegal op */ - 0xc3, 0x08, 0x02, /* JP $0207 */ + 0xc3, 0x07, 0x02, /* JP $0207 */ 0xff /* End of patch */ }; static const Z80Byte load[]= { 0xed, 0xf1, /* ED F0 illegal op */ - 0xc3, 0x08, 0x02, /* JP $0207 */ + 0xc3, 0x07, 0x02, /* JP $0207 */ 0xff /* End of patch */ }; @@ -343,9 +343,9 @@ static void ULA_Video_Shifter(Z80 *z80, Z80Byte val) if (!scr_enable) return; - /* Extra check due to out dodgy ULA emulation + /* Extra check due possibly dodgy ULA emulation */ - if (ULA.y>=0 && ULA.y<SCR_H) + if (ULA.y>=0 && ULA.y<SCR_H && ULA.x<TXT_W) { Uint32 fg,bg; @@ -381,7 +381,7 @@ static void ULA_Video_Shifter(Z80 *z80, Z80Byte val) } } - ULA.x=(ULA.x+1)&0x1f; + ULA.x++; } @@ -397,11 +397,14 @@ static int CheckTimers(Z80 *z80, Z80Val val) /* Debug("NMI\n"); */ } - if (hsync) + if (hsync && !nmigen) { if (last_R&0x40 && !(z80->R&0x40)) { Z80Interrupt(z80,0xff); + ULA.y++; + ULA.c=(ULA.c+1)%8; + ULA.x=0; /* Debug("INTERRUPT\n"); */ } } @@ -464,7 +467,7 @@ void ZX81Init(Z80 *z80) /* Memory size (1 or 16K) */ if (IConfig(CONF_MEMSIZE)==16) - RAMLEN=0x2000; + RAMLEN=0x4000; else RAMLEN=0x400; @@ -606,7 +609,7 @@ Z80Byte ZX81ReadPort(Z80 *z80, Z80Word port) GFXClear(white); ULA.x=0; - ULA.y=0; + ULA.y=-1; ULA.c=7; ULA.release=FALSE; @@ -621,7 +624,7 @@ Z80Byte ZX81ReadPort(Z80 *z80, Z80Word port) ULA.release=FALSE; } - /* If NMI on, turn off the HSYNC generator + /* If NMI off, turn off the HSYNC generator */ if (!nmigen) { |