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collapseos
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collapseos/blk/213

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z80: fix tricky memory initialization issue Among random "better safe than sorry" changes, the real fix is in changing "4" for "5" above _find declaration. This off-by-one error had that word, which is the root word in z80, have a 0x01 prev field instead of a 0x00 one. When all memory was initialized to zero, it didn't matter, we ended up hitting 0 prev and considered ourselves properly at the end of dict. When memory wasn't initialized, however, we would end up jumping at all kinds of places, leading to random behavior.
2020-08-16 06:37:58 +10:00
CREATE ORG 0 ,
CREATE BIN( 0 ,
z80a: de-variable-ize Use straight VARIABLE instead of Z80MEM+. Initially, I used this system to allow z80a to be embedded in a system binary, but now I don't think it's worth it. Compiled, z80a is 2.5k. Sure, it's a sizeable amount of RAM, but I think that even with it in RAM, I'll manage a bootstrap within my most constrained machine, the SMS with 8K.
2020-05-15 05:22:32 +10:00
VARIABLE L1 VARIABLE L2 VARIABLE L3 VARIABLE L4
Copy z80a.fs to disk blocks I don't remove z80a.fs yet because build process needs it, but that will change shortly.
2020-04-20 10:36:13 +10:00
: A 7 ; : B 0 ; : C 1 ; : D 2 ;
: E 3 ; : H 4 ; : L 5 ; : (HL) 6 ;
: BC 0 ; : DE 1 ; : HL 2 ; : AF 3 ; : SP AF ;
: CNZ 0 ; : CZ 1 ; : CNC 2 ; : CC 3 ;
: CPO 4 ; : CPE 5 ; : CP 6 ; : CM 7 ;