Apple-2-Tools/bradgrantham-apple2e
1
0
Fork 0
mirror of https://github.com/bradgrantham/apple2e.git synced 2025-01-17 03:29:52 +00:00
Code Issues Projects Releases Wiki Activity

Make Lemmings start up (but wrong Lemmings...)

Browse Source 
Implement EOR zpg,X
Implement ROL zpg,X (Thanks, Bart and Dad!)
This commit is contained in:
Brad Grantham 2016-12-26 01:34:57 -08:00
parent 4bd25b0cc1
commit 8817b799b6
1 changed files with 18 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
apple2e.cpp
View File

@ -1920,6 +1920,17 @@ struct CPU6502
break; break;
} }
case 0x36: { // ROL zpg,X
unsigned char zpg = (read_pc_inc(bus) + x) & 0xFF;
m = bus.read(zpg);
bool c = isset(C);
flag_change(C, m & 0x01);
set_flags(N | Z, m = (c ? 0x01 : 0x00) | (m << 1));
bus.write(zpg, m);
break;
}
case 0x3E: { // ROL abs, X case 0x3E: { // ROL 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);
@ -2162,6 +2173,13 @@ struct CPU6502
break; break;
} }
case 0x55: { // EOR zpg, X
unsigned char zpg = read_pc_inc(bus) + x;
m = bus.read(zpg & 0xFF);
set_flags(N | Z, a = a ^ m);
break;
}
case 0x41: { // EOR (ind, X) case 0x41: { // EOR (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;