6502 0x20 opcode (Test 20 55 13) Incorrect?

SingleStepTests / ProcessorTests

A language-agnostic JSON-encoded instruction-by-instruction test suite for the 8088, 68000, 65816, 65[c]02 and SPC700 that includes bus activity.

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6502 0x20 opcode (Test 20 55 13) Incorrect? #77

Closed gkjpettet closed 7 months ago

gkjpettet commented 8 months ago

I think there is an issue with test 20 55 13. My CPU emulator passes all tests apart from this one. I think the final status should be:

A:  158
P:  230
PC: 4949 (0x1355)
X:  137
Y:  52

N V - B D I Z C
1 1 - 0 0 1 1 0 

------
Memory
------
Address | Value
341     | AD (173)
379     | 20 (32)
380     | 7E (126)
381     | 01 (1)

pjsoberoi commented 7 months ago

This is a tricky one, I had the same question. The instruction is overwriting itself as it's executing.

Dup of https://github.com/TomHarte/ProcessorTests/issues/65.