mirror of https://git.sr.ht/~rabbits/uxn
53 lines
1.2 KiB
Tal
53 lines
1.2 KiB
Tal
(
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heap functions
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The heap is an area of memory that is written from the bottom up. These
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are a few convenience functions to do that writing.
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There is a global short called "heap" that must be written to before using
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these functions, otherwise the zero page and program memory could be
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overwritten.
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A simple program could use all unallocated memory for the heap like so:
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|0100 @reset
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;my-heap ;heap STA2
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(the rest of your code)
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@my-heap
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Note that if there is a risk that the heap may overflow its bounds, it is
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strongly recommended to check where it is writing to. ";heap LDA2" will
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tell you where the next byte is written.
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)
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@heap $2
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@append-heap-byte ( byte -- )
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,heap LDR2 ( byte heap* )
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INC2k ,heap STR2
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STA
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JMP2r
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@append-heap-short ( short^ -- )
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,heap LDR2 ( short^ heap* )
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INC2k INC2 ,heap STR2
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STA2
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JMP2r
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@append-heap-string ( string* -- )
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( copies a null-terminated string onto the heap, including the null )
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STH2 ,heap LDR2 ( heap* / string* )
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#01 JMP ( skip past INC2r )
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&loop
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INC2r ( heap* / string* )
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LDAkr DUPr STH2k STAr ( heap* / string* byte )
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INC2
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LITr f7 JCNr ( f7 is the value ",&loop" would produce )
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POP2r ( heap* )
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,heap STR2
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JMP2r
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