fork of PCE focusing on macplus, supporting DaynaPort SCSI network emulation
6502: Fix the indirect indexed addressing mode
+14
-6
+14
-6
src/cpu/e6502/ea.c
+14
-6
src/cpu/e6502/ea.c
···
77
77
78
78
unsigned short e6502_get_ea_ind_idx_y (e6502_t *c)
79
79
{
80
-
unsigned short tmp;
80
+
unsigned ial, adl, adh;
81
81
82
82
e6502_get_inst1 (c);
83
83
84
-
tmp = e6502_get_mem16 (c, c->inst[1]);
85
-
c->ea = (tmp + e6502_get_y (c)) & 0xffff;
84
+
ial = c->inst[1];
86
85
87
-
if ((tmp ^ c->ea) & 0xff00) {
88
-
c->ea_page = 1;
86
+
adl = e6502_get_mem8 (c, ial);
87
+
adh = e6502_get_mem8 (c, (ial + 1) & 0xff);
88
+
89
+
adl += e6502_get_y (c);
90
+
91
+
if (adl < 0x100) {
92
+
c->ea_page = 0;
89
93
}
90
94
else {
91
-
c->ea_page = 0;
95
+
c->ea_page = 1;
96
+
adl = adl & 0xff;
97
+
adh = (adh + 1) & 0xff;
92
98
}
99
+
100
+
c->ea = (adh << 8) | adl;
93
101
94
102
return (c->ea);
95
103
}