Apple-2-Tools/bradgrantham-apple2e
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More instructions: Choplifter works

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Implement 0x80 (NOP imm, aka "DOP")
TXS doesn't set flags
Remove 65C02 0x80 (BRA imm)
Add ORA (ind, X)
This commit is contained in:
Brad Grantham 2016-11-30 09:26:19 -08:00
parent ed8dfa33ea
commit 9cf71aa21f
1 changed files with 57 additions and 10 deletions
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67
apple2e.cpp
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@ -1119,6 +1119,11 @@ struct CPU6502
break;
}
case 0x80: { // NOP imm (Choplifter?)
read_pc_inc(bus);
break;
}
case 0x8A: { // TXA
set_flags(N | Z, a = x);
break;
@ -1135,7 +1140,7 @@ struct CPU6502
}
case 0x9A: { // TXS
set_flags(N | Z, s = x);
s = x;
break;
}
@ -1250,15 +1255,6 @@ struct CPU6502
break;
}
case 0x80: { // BRA - 65C02! (Choplifter)
int rel = (read_pc_inc(bus) + 128) % 256 - 128;
clk++;
if((pc + rel) / 256 != pc / 256)
clk++;
pc += rel;
break;
}
case 0x10: { // BPL
int rel = (read_pc_inc(bus) + 128) % 256 - 128;
if(!isset(N)) {
@ -1752,6 +1748,14 @@ struct CPU6502
break;
}
case 0x01: { // ORA (ind, X)
unsigned char zpg = (read_pc_inc(bus) + x) & 0xFF;
int addr = bus.read(zpg) + bus.read((zpg + 1) & 0xFF) * 256;
m = bus.read(addr);
set_flags(N | Z, a = a | m);
break;
}
case 0x15: { // ORA zpg, X
int zpg = (read_pc_inc(bus) + x) & 0xFF;
m = bus.read(zpg);
@ -1852,6 +1856,16 @@ struct CPU6502
break;
}
case 0x3E: { // ROL abs, X
int addr = read_pc_inc(bus) + read_pc_inc(bus) * 256;
m = bus.read(addr + x);
bool c = isset(C);
flag_change(C, m & 0x80);
set_flags(N | Z, m = (c ? 0x01 : 0x00) | (m << 1));
bus.write(addr + x, m);
break;
}
case 0x2A: { // ROL
bool c = isset(C);
flag_change(C, a & 0x80);
@ -2290,6 +2304,37 @@ void cleanup(void)
bool use_fake6502 = false;
struct saved_inst {
int pc;
unsigned char bytes[4];
};
void disassemble_previous_instructions(deque<saved_inst>& previous_instructions)
{
for(auto it : previous_instructions) {
int bytes;
string dis;
tie(bytes, dis) = disassemble_6502(it.pc, it.bytes);
printf("%s\n", dis.c_str());
}
}
const int max_previous_instructions = 100;
void read_instruction_and_save(bus_frontend &bus, int pc, deque<saved_inst>& previous_instructions)
{
saved_inst inst;
inst.pc = pc;
inst.bytes[0] = bus.read(pc + 0);
inst.bytes[1] = bus.read(pc + 1);
inst.bytes[2] = bus.read(pc + 2);
inst.bytes[3] = bus.read(pc + 3);
if(previous_instructions.size() > max_previous_instructions)
previous_instructions.pop_front();
previous_instructions.push_back(inst);
}
string read_bus_and_disassemble(bus_frontend &bus, int pc)
{
int bytes;
@ -2603,6 +2648,8 @@ int main(int argc, char **argv)
if(use_fake6502)
reset6502();
deque<saved_inst> previous_instructions;
APPLE2Einterface::start();
chrono::time_point<chrono::system_clock> then = std::chrono::system_clock::now();