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The 6502 test checks the BRK instruction only with the interrupt disable flag off. The additional 65C02 test makes the humble assumption that the BRK instruction works in general and does not check if…
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```asm
.setcpu "65C02"
.include "opcodes.inc"
```
Result: **cc65/asminc/opcodes.inc(249): Error: Symbol `OPC_EOR_abx' is already defined**
```
$ grep EOR_abx asminc/opcodes.inc
OPC_EOR_abx =…
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Applewin 1.25.0.4
Serial Port set as "TCP"
When Enabling IRQ in ACIA CMD register (with value %00000101) an IRQ signal is generated (properly caught by IRQ handler) but bit 7 of ACIA status Register …
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On csa2, "Cycles question" qkumba said on Oct 25, 2017:
> To summarise, the one-cycle penalty comes from either fetching absolutely across a page boundary (5 cycles):
>
...
>
> or taking a br…
tomcw updated
6 years ago
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I get the following error, if I try to disassemble a (commercial) file.
The file is 65536 bytes in size.
test.cfg looks like this:
```
GLOBAL {
CPU "65C02"…
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Use CTRL-P and CTRL-N (which should be the traditional Unix shell codes) to bring up at least the last input. This probably requires the ability to get multi-byte input(?)
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From csa2, "Cycles question"
For the y-reg, it would read from $FF and $100.
This small program proves it.
300: LDY #0
LDA ($FF),Y
JMP $FDDA
00:61
FF:0 60
300:A0 00 B1 FF 4C DA…
tomcw updated
7 years ago
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I know that it isn't kosher to actually write applications in Forth - Forth programmers are supposed to only write new system implementations - but I couldn't help myself.
https://github.com/MitchB…
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cc65 self modifies jmpvec which is not in zero page.
In the obscure case where it's mid modifying jmpvec takes an interrupt and then the irq handler causes the same execution path the interrupt cor…
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https://github.com/zellyn/a2audit/issues/5
John Brooks on Twitter: https://twitter.com/JBrooksBSI/status/853004037674774528
>It enables LC writes by utilizing 6502 false read to do 2x reads with one…
tomcw updated
7 years ago