Find limit of recursion: Difference between revisions
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Puppydrum64 (talk | contribs) |
Puppydrum64 (talk | contribs) |
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Reading the current stack pointer is unreliable, as there is no requirement that the stack be "aligned" in any way. Unlike the 8086 and Z80, which require all pushes/pops to be exactly two bytes, the 6502's stack will likely contain both 1 byte registers and 2 byte return addresses. It's much easier to use a stack canary. Pick a value that is unlikely to be used in your program. |
Reading the current stack pointer is unreliable, as there is no requirement that the stack be "aligned" in any way. Unlike the 8086 and Z80, which require all pushes/pops to be exactly two bytes, the 6502's stack will likely contain both 1 byte registers and 2 byte return addresses. It's much easier to use a stack canary. Pick a value that is unlikely to be used in your program. |
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<lang 6502asm> |
<lang 6502asm>;beginning of your program |
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;beginning of your program |
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lda #$BE |
lda #$BE |
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sta $0100 |
sta $0100 |
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ldx #$ff |
ldx #$ff |
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txs ;stack pointer is set to $FF |
txs ;stack pointer is set to $FF |
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;later... |
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lda $0100 ;if this no longer equals $BE the stack has overflowed |
lda $0100 ;if this no longer equals $BE the stack has overflowed |
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