Apple-2-Tools/bradgrantham-apple2e
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Make instruction timing a lot more correct

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Fix up clock timing on absolute-indexed, indirect-indexed, and branch instructions
Emitted clock ticks now match up with emulated and video recorded beep sound
(code to save off and postprocess ticks not checked in)
This commit is contained in:
Brad Grantham 2016-11-23 20:31:30 -08:00
parent 873aeb596f
commit 4085189d9f
1 changed files with 92 additions and 36 deletions
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128
apple2e.cpp
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@ -41,7 +41,7 @@ struct system_clock
unsigned long long value = 0; unsigned long long value = 0;
operator unsigned long long() const { return value; } operator unsigned long long() const { return value; }
unsigned long long operator+=(unsigned long long i) { return value += i; } unsigned long long operator+=(unsigned long long i) { return value += i; }
unsigned long long operator++() { return value ++; } unsigned long long operator++(int) { unsigned long long v = value; value ++; return v; }
} clk; } clk;
struct SoftSwitch struct SoftSwitch
@ -349,6 +349,7 @@ struct MAINboard : board_base
} }
if(addr == 0xC030) { if(addr == 0xC030) {
if(debug & DEBUG_RW) printf("read SPKR, force 0x00\n"); if(debug & DEBUG_RW) printf("read SPKR, force 0x00\n");
// printf("%llu\n", clk.value); <-- clock is more or less correct at this moment
// click // click
data = 0x00; data = 0x00;
return true; return true;
@ -819,32 +820,93 @@ struct CPU6502
case 0x10: { // BPL case 0x10: { // BPL
int rel = (read_pc_inc(bus) + 128) % 256 - 128; int rel = (read_pc_inc(bus) + 128) % 256 - 128;
if(!isset(N)) if(!isset(N)) {
clk++;
if((pc + rel) / 256 != pc / 256)
clk++;
pc += rel; pc += rel;
}
break; break;
} }
case 0x50: { // BVC case 0x50: { // BVC
int rel = (read_pc_inc(bus) + 128) % 256 - 128; int rel = (read_pc_inc(bus) + 128) % 256 - 128;
if(!isset(V)) if(!isset(V)) {
clk++;
if((pc + rel) / 256 != pc / 256)
clk++;
pc += rel; pc += rel;
}
break; break;
} }
case 0x70: { // BVS case 0x70: { // BVS
int rel = (read_pc_inc(bus) + 128) % 256 - 128; int rel = (read_pc_inc(bus) + 128) % 256 - 128;
if(isset(V)) if(isset(V)) {
clk++;
if((pc + rel) / 256 != pc / 256)
clk++;
pc += rel; pc += rel;
}
break; break;
} }
case 0x30: { // BMI case 0x30: { // BMI
int rel = (read_pc_inc(bus) + 128) % 256 - 128; int rel = (read_pc_inc(bus) + 128) % 256 - 128;
if(isset(N)) if(isset(N)) {
clk++;
if((pc + rel) / 256 != pc / 256)
clk++;
pc += rel; pc += rel;
}
break; break;
} }
case 0x90: { // BCC
int rel = (read_pc_inc(bus) + 128) % 256 - 128;
if(!isset(C)) {
clk++;
if((pc + rel) / 256 != pc / 256)
clk++;
pc += rel;
}
break;
}
case 0xB0: { // BCS
int rel = (read_pc_inc(bus) + 128) % 256 - 128;
if(isset(C)) {
clk++;
if((pc + rel) / 256 != pc / 256)
clk++;
pc += rel;
}
break;
}
case 0xD0: { // BNE
int rel = (read_pc_inc(bus) + 128) % 256 - 128;
if(!isset(Z)) {
clk++;
if((pc + rel) / 256 != pc / 256)
clk++;
pc += rel;
}
break;
}
case 0xF0: { // BEQ
int rel = (read_pc_inc(bus) + 128) % 256 - 128;
if(isset(Z)) {
clk++;
if((pc + rel) / 256 != pc / 256)
clk++;
pc += rel;
}
break;
}
case 0xA1: { // LDA (ind, X) case 0xA1: { // LDA (ind, X)
unsigned char zpg = (read_pc_inc(bus) + x) & 0xFF; unsigned char zpg = (read_pc_inc(bus) + x) & 0xFF;
int addr = bus.read(zpg) + bus.read((zpg + 1) & 0xFF) * 256; int addr = bus.read(zpg) + bus.read((zpg + 1) & 0xFF) * 256;
@ -862,6 +924,8 @@ struct CPU6502
case 0xB1: { // LDA ind, Y case 0xB1: { // LDA ind, Y
unsigned char zpg = read_pc_inc(bus); unsigned char zpg = read_pc_inc(bus);
int addr = bus.read(zpg) + bus.read((zpg + 1) & 0xFF) * 256 + y; int addr = bus.read(zpg) + bus.read((zpg + 1) & 0xFF) * 256 + y;
if((addr - y) / 256 != addr / 256)
clk++;
set_flags(N | Z, a = bus.read(addr)); set_flags(N | Z, a = bus.read(addr));
break; break;
} }
@ -875,6 +939,8 @@ struct CPU6502
case 0xDD: { // CMP abs, X case 0xDD: { // CMP abs, X
int addr = read_pc_inc(bus) + read_pc_inc(bus) * 256; int addr = read_pc_inc(bus) + read_pc_inc(bus) * 256;
m = bus.read(addr + x); m = bus.read(addr + x);
if((addr + x) / 256 != addr / 256)
clk++;
flag_change(C, m <= a); flag_change(C, m <= a);
set_flags(N | Z, m = a - m); set_flags(N | Z, m = a - m);
break; break;
@ -883,6 +949,8 @@ struct CPU6502
case 0xD9: { // CMP abs, Y case 0xD9: { // CMP abs, Y
int addr = read_pc_inc(bus) + read_pc_inc(bus) * 256; int addr = read_pc_inc(bus) + read_pc_inc(bus) * 256;
m = bus.read(addr + y); m = bus.read(addr + y);
if((addr + y) / 256 != addr / 256)
clk++;
flag_change(C, m <= a); flag_change(C, m <= a);
set_flags(N | Z, m = a - m); set_flags(N | Z, m = a - m);
break; break;
@ -891,12 +959,16 @@ struct CPU6502
case 0xB9: { // LDA abs, Y case 0xB9: { // LDA abs, Y
int addr = read_pc_inc(bus) + read_pc_inc(bus) * 256; int addr = read_pc_inc(bus) + read_pc_inc(bus) * 256;
set_flags(N | Z, a = bus.read(addr + y)); set_flags(N | Z, a = bus.read(addr + y));
if((addr + y) / 256 != addr / 256)
clk++;
break; break;
} }
case 0xBD: { // LDA abs, X case 0xBD: { // LDA abs, X
int addr = read_pc_inc(bus) + read_pc_inc(bus) * 256; int addr = read_pc_inc(bus) + read_pc_inc(bus) * 256;
set_flags(N | Z, a = bus.read(addr + x)); set_flags(N | Z, a = bus.read(addr + x));
if((addr + x) / 256 != addr / 256)
clk++;
break; break;
} }
@ -923,6 +995,8 @@ struct CPU6502
case 0xF1: { // SBC ind, Y case 0xF1: { // SBC ind, Y
unsigned char zpg = read_pc_inc(bus); unsigned char zpg = read_pc_inc(bus);
int addr = bus.read(zpg) + bus.read((zpg + 1) & 0xff) * 256 + y; int addr = bus.read(zpg) + bus.read((zpg + 1) & 0xff) * 256 + y;
if((addr - y) / 256 != addr / 256)
clk++;
m = bus.read(addr); m = bus.read(addr);
int borrow = isset(C) ? 0 : 1; int borrow = isset(C) ? 0 : 1;
flag_change(C, !(a < (m + borrow))); flag_change(C, !(a < (m + borrow)));
@ -933,6 +1007,8 @@ struct CPU6502
case 0xFD: { // SBC abs, X case 0xFD: { // SBC abs, X
int addr = read_pc_inc(bus) + read_pc_inc(bus) * 256 + x; int addr = read_pc_inc(bus) + read_pc_inc(bus) * 256 + x;
if((addr - x) / 256 != addr / 256)
clk++;
unsigned char m = bus.read(addr); unsigned char m = bus.read(addr);
int borrow = isset(C) ? 0 : 1; int borrow = isset(C) ? 0 : 1;
flag_change(C, !(a < (m + borrow))); flag_change(C, !(a < (m + borrow)));
@ -972,6 +1048,8 @@ struct CPU6502
case 0x79: { // ADC abs, Y case 0x79: { // ADC abs, Y
int addr = read_pc_inc(bus) + read_pc_inc(bus) * 256 + y; int addr = read_pc_inc(bus) + read_pc_inc(bus) * 256 + y;
if((addr - y) / 256 != addr / 256)
clk++;
m = bus.read(addr); m = bus.read(addr);
int carry = isset(C) ? 1 : 0; int carry = isset(C) ? 1 : 0;
flag_change(C, (int)(a + m + carry) > 0xFF); flag_change(C, (int)(a + m + carry) > 0xFF);
@ -1059,6 +1137,8 @@ struct CPU6502
case 0x11: { // ORA (ind), Y case 0x11: { // ORA (ind), Y
unsigned char zpg = read_pc_inc(bus); unsigned char zpg = read_pc_inc(bus);
int addr = bus.read(zpg) + bus.read((zpg + 1) & 0xFF) * 256 + y; int addr = bus.read(zpg) + bus.read((zpg + 1) & 0xFF) * 256 + y;
if((addr - y) / 256 != addr / 256)
clk++;
m = bus.read(addr); m = bus.read(addr);
set_flags(N | Z, a = a | m); set_flags(N | Z, a = a | m);
break; break;
@ -1144,9 +1224,8 @@ struct CPU6502
break; break;
} }
case 0x4C: { case 0x4C: { // JMP
int addr = read_pc_inc(bus) + read_pc_inc(bus) * 256; int addr = read_pc_inc(bus) + read_pc_inc(bus) * 256;
// JMP
pc = addr; pc = addr;
break; break;
} }
@ -1221,6 +1300,8 @@ struct CPU6502
case 0xBE: { // LDX case 0xBE: { // LDX
int addr = read_pc_inc(bus) + read_pc_inc(bus) * 256 + y; int addr = read_pc_inc(bus) + read_pc_inc(bus) * 256 + y;
if((addr - y) / 256 != addr / 256)
clk++;
set_flags(N | Z, x = bus.read(addr)); set_flags(N | Z, x = bus.read(addr));
break; break;
} }
@ -1304,6 +1385,8 @@ struct CPU6502
case 0x51: { // EOR case 0x51: { // EOR
unsigned char zpg = read_pc_inc(bus); unsigned char zpg = read_pc_inc(bus);
int addr = bus.read(zpg) + bus.read((zpg + 1) & 0xFF) * 256 + y; int addr = bus.read(zpg) + bus.read((zpg + 1) & 0xFF) * 256 + y;
if((addr - y) / 256 != addr / 256)
clk++;
m = bus.read(addr); m = bus.read(addr);
set_flags(N | Z, a = a ^ m); set_flags(N | Z, a = a ^ m);
break; break;
@ -1312,6 +1395,8 @@ struct CPU6502
case 0xD1: { // CMP case 0xD1: { // CMP
unsigned char zpg = read_pc_inc(bus); unsigned char zpg = read_pc_inc(bus);
int addr = bus.read(zpg) + bus.read((zpg + 1) & 0xFF) * 256 + y; int addr = bus.read(zpg) + bus.read((zpg + 1) & 0xFF) * 256 + y;
if((addr - y) / 256 != addr / 256)
clk++;
m = bus.read(addr); m = bus.read(addr);
flag_change(C, m <= a); flag_change(C, m <= a);
set_flags(N | Z, m = a - m); set_flags(N | Z, m = a - m);
@ -1365,34 +1450,6 @@ struct CPU6502
break; break;
} }
case 0x90: { // BCC
int rel = (read_pc_inc(bus) + 128) % 256 - 128;
if(!isset(C))
pc += rel;
break;
}
case 0xB0: { // BCS
int rel = (read_pc_inc(bus) + 128) % 256 - 128;
if(isset(C))
pc += rel;
break;
}
case 0xD0: { // BNE
int rel = (read_pc_inc(bus) + 128) % 256 - 128;
if(!isset(Z))
pc += rel;
break;
}
case 0xF0: { // BEQ
int rel = (read_pc_inc(bus) + 128) % 256 - 128;
if(isset(Z))
pc += rel;
break;
}
case 0x85: { // STA case 0x85: { // STA
unsigned char zpg = read_pc_inc(bus); unsigned char zpg = read_pc_inc(bus);
bus.write(zpg, a); bus.write(zpg, a);
@ -1814,7 +1871,6 @@ int main(int argc, char **argv)
step6502(); step6502();
else else
cpu.cycle(bus); cpu.cycle(bus);
printf("clock = %llu\n", clk.value);
APPLE2Einterface::DisplayMode mode = mainboard->TEXT ? APPLE2Einterface::TEXT : (mainboard->HIRES ? APPLE2Einterface::HIRES : APPLE2Einterface::LORES); APPLE2Einterface::DisplayMode mode = mainboard->TEXT ? APPLE2Einterface::TEXT : (mainboard->HIRES ? APPLE2Einterface::HIRES : APPLE2Einterface::LORES);
int page = mainboard->PAGE2 ? 1 : 0; int page = mainboard->PAGE2 ? 1 : 0;