Apple-2-Tools/bradgrantham-apple2e
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Fix ADC abs (was accidentally adding Y to address)
Also handle bank switch registers on write
Initialize CPU6502 registers to 0 to match fake6502
    Avoid spurious differences
Implement more instructions
    ADC (ind), Y
    ADC abs, X
    ORA zpg, X
This commit is contained in:
Brad Grantham 2016-11-28 13:27:52 -08:00
parent 43bb5d2663
commit f107f4b23d
1 changed files with 48 additions and 2 deletions
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50
apple2e.cpp
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@ -568,6 +568,7 @@ struct MAINboard : board_base
{
keyboard_buffer.push_back(k);
}
typedef std::function<bool (int addr, unsigned char data)> display_write_func;
display_write_func display_write;
typedef std::function<void (char *audiobuffer, size_t dist)> audio_flush_func;
@ -781,6 +782,15 @@ struct MAINboard : board_base
return true;
}
}
if((addr & 0xFFF0) == 0xC080) {
C08X_bank = ((addr >> 3) & 1) ? BANK1 : BANK2;
C08X_write_RAM = addr & 1;
int read_ROM = ((addr >> 1) & 1) ^ C08X_write_RAM;
C08X_read_RAM = !read_ROM;
if(debug & DEBUG_SWITCH) printf("write %04X switch, %s, %d write_RAM, %d read_RAM\n", addr, (C08X_bank == BANK1) ? "BANK1" : "BANK2", C08X_write_RAM, C08X_read_RAM);
data = 0x00;
return true;
}
if(addr == 0xC010) {
if(debug & DEBUG_RW) printf("write KBDSTRB\n");
if(!keyboard_buffer.empty()) {
@ -902,6 +912,10 @@ struct CPU6502
} exception;
CPU6502(system_clock& clk_) :
clk(clk_),
a(0),
x(0),
y(0),
s(0),
p(0x20),
exception(RESET)
{
@ -1408,8 +1422,21 @@ struct CPU6502
break;
}
case 0x71: { // ADC (ind), Y
unsigned char zpg = read_pc_inc(bus);
int addr = bus.read(zpg) + bus.read((zpg + 1) & 0xFF) * 256 + y;
if((addr - y) / 256 != addr / 256)
clk++;
m = bus.read(addr);
int carry = isset(C) ? 1 : 0;
flag_change(C, (int)(a + m + carry) > 0xFF);
flag_change(V, adc_overflow(a, m, carry));
set_flags(N | Z, a = a + m + carry);
break;
}
case 0x6D: { // ADC abs
int addr = read_pc_inc(bus) + read_pc_inc(bus) * 256 + y;
int addr = read_pc_inc(bus) + read_pc_inc(bus) * 256;
m = bus.read(addr);
int carry = isset(C) ? 1 : 0;
flag_change(C, (int)(a + m + carry) > 0xFF);
@ -1428,6 +1455,18 @@ struct CPU6502
break;
}
case 0x7D: { // ADC abs, X
int addr = read_pc_inc(bus) + read_pc_inc(bus) * 256 + x;
if((addr - x) / 256 != addr / 256)
clk++;
m = bus.read(addr);
int carry = isset(C) ? 1 : 0;
flag_change(C, (int)(a + m + carry) > 0xFF);
flag_change(V, adc_overflow(a, m, carry));
set_flags(N | Z, a = a + m + carry);
break;
}
case 0x79: { // ADC abs, Y
int addr = read_pc_inc(bus) + read_pc_inc(bus) * 256 + y;
if((addr - y) / 256 != addr / 256)
@ -1534,6 +1573,13 @@ struct CPU6502
break;
}
case 0x15: { // ORA zpg, X
int zpg = (read_pc_inc(bus) + x) & 0xFF;
m = bus.read(zpg);
set_flags(N | Z, a = a | m);
break;
}
case 0x0D: { // ORA abs
int addr = read_pc_inc(bus) + read_pc_inc(bus) * 256;
m = bus.read(addr);
@ -2030,7 +2076,7 @@ void cleanup(void)
fflush(stderr);
}
bool use_fake6502 = true;
bool use_fake6502 = false;
string read_bus_and_disassemble(bus_frontend &bus, int pc)
{