Apple-2-Tools/bradgrantham-apple2e
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add ADC(zpg)

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This commit is contained in:
Brad Grantham 2018-07-31 12:07:42 -07:00
parent ea3930a8f0
commit 6f92ffa096
1 changed files with 26 additions and 4 deletions
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30
apple2e.cpp
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@ -817,6 +817,8 @@ struct MAINboard : board_base
}
virtual bool write(int addr, unsigned char data)
{
if(addr == 0x6000)
printf("$6000 = $%02X\n", data);
#if 0
if(text_page1.write(addr, data) ||
text_page1x.write(addr, data) ||
@ -1082,7 +1084,7 @@ struct CPU6502
/* 0x4- */ 6, 6, -1, -1, -1, 3, 5, -1, 3, 2, 2, -1, 3, 4, 6, -1,
/* 0x5- */ 2, 5, -1, -1, -1, 4, 6, -1, 2, 4, -1, -1, -1, 4, 7, -1,
/* 0x6- */ 6, 6, -1, -1, -1, 3, 5, -1, 4, 2, 2, -1, 5, 4, 6, -1,
/* 0x7- */ 2, 5, -1, -1, -1, 4, 6, -1, 2, 4, -1, -1, -1, 4, 7, -1,
/* 0x7- */ 2, 5, 5, -1, -1, 4, 6, -1, 2, 4, -1, -1, -1, 4, 7, -1,
/* 0x8- */ 2, 6, -1, -1, 3, 3, 3, -1, 2, -1, 2, -1, 4, 4, 4, -1,
/* 0x9- */ 2, 6, 5, -1, 4, 4, 4, -1, 2, 5, 2, -1, -1, 5, -1, -1,
/* 0xA- */ 2, 6, 2, -1, 3, 3, 3, -1, 2, 2, 2, -1, 4, 4, 4, -1,
@ -2364,19 +2366,39 @@ struct CPU6502
break;
}
case 0x92: { // STA (zpg), 65C02 instruction!
case 0x92: { // STA (zpg), 65C02 instruction
unsigned char zpg = read_pc_inc(bus);
int addr = bus.read(zpg) + bus.read((zpg + 1) & 0xFF) * 256;
bus.write(addr, a);
break;
}
case 0x3A: { // DEC
case 0x72: { // ADC (zpg), 65C02 instruction
unsigned char zpg = read_pc_inc(bus);
int addr = bus.read(zpg) + bus.read((zpg + 1) & 0xFF) * 256;
m = bus.read(addr);
int carry = isset(C) ? 1 : 0;
if(isset(D)) {
unsigned char bcd = a / 16 * 10 + a % 16;
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;
}
case 0x3A: { // DEC, 65C02 instruction
set_flags(N | Z, a = a - 1);
break;
}
case 0x1A: { // INC
case 0x1A: { // INC, 65C02 instruction
set_flags(N | Z, a = a + 1);
break;
}