Apple-2-Tools/bradgrantham-apple2e
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BCD mode; SED; AND zpg, X

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This commit is contained in:
Brad Grantham 2016-11-29 00:25:04 -08:00
parent 91e8aaf726
commit cfe9d962d8
1 changed files with 178 additions and 45 deletions
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223
apple2e.cpp
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@ -876,6 +876,24 @@ void write6502(uint16_t address, uint8_t value)
}; };
bool sbc_overflow_d(unsigned char a, unsigned char b, int borrow)
{
// ??
signed char a_ = a;
signed char b_ = b;
signed short c = a_ - (b_ + borrow);
return (c < 0) || (c > 99);
}
bool adc_overflow_d(unsigned char a, unsigned char b, int carry)
{
// ??
signed char a_ = a;
signed char b_ = b;
signed short c = a_ + b_ + carry;
return (c < 0) || (c > 99);
}
bool sbc_overflow(unsigned char a, unsigned char b, int borrow) bool sbc_overflow(unsigned char a, unsigned char b, int borrow)
{ {
signed char a_ = a; signed char a_ = a;
@ -1116,6 +1134,11 @@ struct CPU6502
break; break;
} }
case 0xF8: { // SED
flag_set(D);
break;
}
case 0xD8: { // CLD case 0xD8: { // CLD
flag_clear(D); flag_clear(D);
break; break;
@ -1368,9 +1391,17 @@ struct CPU6502
unsigned char zpg = (read_pc_inc(bus) + x) & 0xFF; unsigned char zpg = (read_pc_inc(bus) + x) & 0xFF;
m = bus.read(zpg); m = bus.read(zpg);
int borrow = isset(C) ? 0 : 1; int borrow = isset(C) ? 0 : 1;
flag_change(C, !(a < (m + borrow))); if(isset(D)) {
flag_change(V, sbc_overflow(a, m, borrow)); unsigned char bcd = a / 16 * 10 + a % 16;
set_flags(N | Z, a = a - (m + borrow)); flag_change(C, !(bcd < m + borrow));
flag_change(V, sbc_overflow_d(bcd, m, borrow));
set_flags(N | Z, bcd = bcd - (m + borrow));
a = bcd / 10 * 16 + bcd % 10;
} else {
flag_change(C, !(a < (m + borrow)));
flag_change(V, sbc_overflow(a, m, borrow));
set_flags(N | Z, a = a - (m + borrow));
}
break; break;
} }
@ -1378,9 +1409,17 @@ struct CPU6502
unsigned char zpg = read_pc_inc(bus); unsigned char zpg = read_pc_inc(bus);
m = bus.read(zpg); m = bus.read(zpg);
int borrow = isset(C) ? 0 : 1; int borrow = isset(C) ? 0 : 1;
flag_change(C, !(a < (m + borrow))); if(isset(D)) {
flag_change(V, sbc_overflow(a, m, borrow)); unsigned char bcd = a / 16 * 10 + a % 16;
set_flags(N | Z, a = a - (m + borrow)); flag_change(C, !(bcd < m + borrow));
flag_change(V, sbc_overflow_d(bcd, m, borrow));
set_flags(N | Z, bcd = bcd - (m + borrow));
a = bcd / 10 * 16 + bcd % 10;
} else {
flag_change(C, !(a < (m + borrow)));
flag_change(V, sbc_overflow(a, m, borrow));
set_flags(N | Z, a = a - (m + borrow));
}
break; break;
} }
@ -1391,9 +1430,17 @@ struct CPU6502
clk++; 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))); if(isset(D)) {
flag_change(V, sbc_overflow(a, m, borrow)); unsigned char bcd = a / 16 * 10 + a % 16;
set_flags(N | Z, a = a - (m + borrow)); flag_change(C, !(bcd < m + borrow));
flag_change(V, sbc_overflow_d(bcd, m, borrow));
set_flags(N | Z, bcd = bcd - (m + borrow));
a = bcd / 10 * 16 + bcd % 10;
} else {
flag_change(C, !(a < (m + borrow)));
flag_change(V, sbc_overflow(a, m, borrow));
set_flags(N | Z, a = a - (m + borrow));
}
break; break;
} }
@ -1403,9 +1450,17 @@ struct CPU6502
clk++; 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))); if(isset(D)) {
flag_change(V, sbc_overflow(a, m, borrow)); unsigned char bcd = a / 16 * 10 + a % 16;
set_flags(N | Z, a = a - (m + borrow)); flag_change(C, !(bcd < m + borrow));
flag_change(V, sbc_overflow_d(bcd, m, borrow));
set_flags(N | Z, bcd = bcd - (m + borrow));
a = bcd / 10 * 16 + bcd % 10;
} else {
flag_change(C, !(a < (m + borrow)));
flag_change(V, sbc_overflow(a, m, borrow));
set_flags(N | Z, a = a - (m + borrow));
}
break; break;
} }
@ -1415,9 +1470,17 @@ struct CPU6502
clk++; 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))); if(isset(D)) {
flag_change(V, sbc_overflow(a, m, borrow)); unsigned char bcd = a / 16 * 10 + a % 16;
set_flags(N | Z, a = a - (m + borrow)); flag_change(C, !(bcd < m + borrow));
flag_change(V, sbc_overflow_d(bcd, m, borrow));
set_flags(N | Z, bcd = bcd - (m + borrow));
a = bcd / 10 * 16 + bcd % 10;
} else {
flag_change(C, !(a < (m + borrow)));
flag_change(V, sbc_overflow(a, m, borrow));
set_flags(N | Z, a = a - (m + borrow));
}
break; break;
} }
@ -1425,18 +1488,34 @@ struct CPU6502
int addr = read_pc_inc(bus) + read_pc_inc(bus) * 256; int addr = read_pc_inc(bus) + read_pc_inc(bus) * 256;
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))); if(isset(D)) {
flag_change(V, sbc_overflow(a, m, borrow)); unsigned char bcd = a / 16 * 10 + a % 16;
set_flags(N | Z, a = a - (m + borrow)); flag_change(C, !(bcd < m + borrow));
flag_change(V, sbc_overflow_d(bcd, m, borrow));
set_flags(N | Z, bcd = bcd - (m + borrow));
a = bcd / 10 * 16 + bcd % 10;
} else {
flag_change(C, !(a < (m + borrow)));
flag_change(V, sbc_overflow(a, m, borrow));
set_flags(N | Z, a = a - (m + borrow));
}
break; break;
} }
case 0xE9: { // SBC imm case 0xE9: { // SBC imm
unsigned char m = read_pc_inc(bus); unsigned char m = read_pc_inc(bus);
int borrow = isset(C) ? 0 : 1; int borrow = isset(C) ? 0 : 1;
flag_change(C, !(a < (m + borrow))); if(isset(D)) {
flag_change(V, sbc_overflow(a, m, borrow)); unsigned char bcd = a / 16 * 10 + a % 16;
set_flags(N | Z, a = a - (m + borrow)); flag_change(C, !(bcd < m + borrow));
flag_change(V, sbc_overflow_d(bcd, m, borrow));
set_flags(N | Z, bcd = bcd - (m + borrow));
a = bcd / 10 * 16 + bcd % 10;
} else {
flag_change(C, !(a < (m + borrow)));
flag_change(V, sbc_overflow(a, m, borrow));
set_flags(N | Z, a = a - (m + borrow));
}
break; break;
} }
@ -1447,9 +1526,17 @@ struct CPU6502
clk++; 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); if(isset(D)) {
flag_change(V, adc_overflow(a, m, carry)); unsigned char bcd = a / 16 * 10 + a % 16;
set_flags(N | Z, a = a + m + carry); flag_change(C, (int)(bcd + m + carry) > 99);
flag_change(V, adc_overflow_d(bcd, m, carry));
set_flags(N | Z, bcd = bcd + m + carry);
a = bcd / 10 * 16 + bcd % 10;
} else {
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; break;
} }
@ -1457,9 +1544,17 @@ struct CPU6502
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); m = bus.read(addr);
int carry = isset(C) ? 1 : 0; int carry = isset(C) ? 1 : 0;
flag_change(C, (int)(a + m + carry) > 0xFF); if(isset(D)) {
flag_change(V, adc_overflow(a, m, carry)); unsigned char bcd = a / 16 * 10 + a % 16;
set_flags(N | Z, a = a + m + carry); flag_change(C, (int)(bcd + m + carry) > 99);
flag_change(V, adc_overflow_d(bcd, m, carry));
set_flags(N | Z, bcd = bcd + m + carry);
a = bcd / 10 * 16 + bcd % 10;
} else {
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; break;
} }
@ -1467,9 +1562,17 @@ struct CPU6502
unsigned char zpg = read_pc_inc(bus); unsigned char zpg = read_pc_inc(bus);
m = bus.read(zpg); m = bus.read(zpg);
int carry = isset(C) ? 1 : 0; int carry = isset(C) ? 1 : 0;
flag_change(C, (int)(a + m + carry) > 0xFF); if(isset(D)) {
flag_change(V, adc_overflow(a, m, carry)); unsigned char bcd = a / 16 * 10 + a % 16;
set_flags(N | Z, a = a + m + carry); flag_change(C, (int)(bcd + m + carry) > 99);
flag_change(V, adc_overflow_d(bcd, m, carry));
set_flags(N | Z, bcd = bcd + m + carry);
a = bcd / 10 * 16 + bcd % 10;
} else {
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; break;
} }
@ -1479,9 +1582,17 @@ struct CPU6502
clk++; 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); if(isset(D)) {
flag_change(V, adc_overflow(a, m, carry)); unsigned char bcd = a / 16 * 10 + a % 16;
set_flags(N | Z, a = a + m + carry); flag_change(C, (int)(bcd + m + carry) > 99);
flag_change(V, adc_overflow_d(bcd, m, carry));
set_flags(N | Z, bcd = bcd + m + carry);
a = bcd / 10 * 16 + bcd % 10;
} else {
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; break;
} }
@ -1491,18 +1602,34 @@ struct CPU6502
clk++; 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); if(isset(D)) {
flag_change(V, adc_overflow(a, m, carry)); unsigned char bcd = a / 16 * 10 + a % 16;
set_flags(N | Z, a = a + m + carry); flag_change(C, (int)(bcd + m + carry) > 99);
flag_change(V, adc_overflow_d(bcd, m, carry));
set_flags(N | Z, bcd = bcd + m + carry);
a = bcd / 10 * 16 + bcd % 10;
} else {
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; break;
} }
case 0x69: { // ADC case 0x69: { // ADC
m = read_pc_inc(bus); m = read_pc_inc(bus);
int carry = isset(C) ? 1 : 0; int carry = isset(C) ? 1 : 0;
flag_change(C, (int)(a + m + carry) > 0xFF); if(isset(D)) {
flag_change(V, adc_overflow(a, m, carry)); unsigned char bcd = a / 16 * 10 + a % 16;
set_flags(N | Z, a = a + m + carry); flag_change(C, (int)(bcd + m + carry) > 99);
flag_change(V, adc_overflow_d(bcd, m, carry));
set_flags(N | Z, bcd = bcd + m + carry);
a = bcd / 10 * 16 + bcd % 10;
} else {
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; break;
} }
@ -1637,6 +1764,12 @@ struct CPU6502
break; break;
} }
case 0x35: { // AND zpg, X
int zpg = (read_pc_inc(bus) + x) & 0xFF;
set_flags(N | Z, a = a & bus.read(zpg));
break;
}
case 0x31: { // AND (ind), y case 0x31: { // AND (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;
@ -2389,13 +2522,13 @@ int main(int argc, char **argv)
MAINboard::audio_flush_func audio; MAINboard::audio_flush_func audio;
if(have_audio) if(have_audio)
audio = [aodev](char *buf, size_t sz){ audio = [aodev](char *buf, size_t sz){
static char prev_sample; // static char prev_sample;
for(int i = 0; i < sz; i++) // for(int i = 0; i < sz; i++)
if(buf[i] != prev_sample) { // if(buf[i] != prev_sample) {
ao_play(aodev, buf, sz); ao_play(aodev, buf, sz);
break; // break;
} // }
prev_sample = buf[sz - 1]; // prev_sample = buf[sz - 1];
}; };
else else
audio = [](char *buf, size_t sz){}; audio = [](char *buf, size_t sz){};