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Bug fix to calculating relative branches

This commit is contained in:
Leeland Heins 2019-01-25 23:13:16 -06:00 committed by GitHub
parent 18e913da23
commit 566ab4fb28
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GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 8 additions and 2 deletions
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da65.pl
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@ -605,7 +605,7 @@ my %opcodes = (
'modesub' => \&mode_Absolute,
'mnemonic' => 'LDY'
},
# Absolute,Y LDY Abs,X BC 3 4
# Absolute,X LDY Abs,X BC 3 4
0xbc => {
'modesub' => \&mode_Absolute_X,
'mnemonic' => 'LDY'
@ -1157,7 +1157,13 @@ sub mode_Indirect_Zero_Page {
sub mode_Relative {
my ($addr, $instr) = @_;
my $rel = ($addr + $base) - (255 - $bytes[$addr + 1] - 1);
#my $rel = ($addr + $base) - (255 - $bytes[$addr + 1] - 1);
my $rel = ($addr + $base) - (254 - $bytes[$addr + 1]);
if ($bytes[$addr + 1] < 127) {
$rel += 256;
}
#print sprintf("addr=%04x base=%04x op=%02x foo=%02x rel=%02x\n", $addr, $base, $bytes[$addr + 1], (255 - $bytes[$addr + 1] - 1), $rel);
#print sprintf("addr=%d base=%d op=%d foo=%d rel=%d\n", $addr, $base, $bytes[$addr + 1], (255 - $bytes[$addr + 1] - 1), $rel);
if ($input_mode) {
print uc sprintf("%04x: %3.3s \$%04x\n", $addr + $base, $instr, $rel);
} else {