64 lines
1.3 KiB
Plaintext
64 lines
1.3 KiB
Plaintext
;license:MIT
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;(c) 2018 by 4am
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;
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; common assembler macros
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;
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; for functions that take parameters on the stack
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; set (PARAM) to point to the parameters and
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; move the stack pointer to the first byte after the parameters
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; clobbers A,X
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!macro PARAMS_ON_STACK .bytes {
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pla
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sta PARAM
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plx
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stx PARAM+1
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lda #.bytes
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clc
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adc PARAM
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bcc +
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inx
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+ phx
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pha
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}
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; for functions that take parameters on the stack
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; load a 16-bit value from the parameters on the stack into A (low) and Y (high)
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; (assumes PARAMS_ON_STACK was used first)
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!macro LDPARAM .offset {
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ldy #.offset+1
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lda (PARAM),y
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pha
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dey
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lda (PARAM),y
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ply
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}
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; load the address of .ptr into A (low) and Y (high)
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!macro LDADDR .ptr {
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lda #<.ptr
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ldy #>.ptr
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}
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; load a 16-bit value into A (low) and Y (high)
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!macro LDAY .ptr {
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lda .ptr
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ldy .ptr+1
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}
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; store a 16-bit value from A (low) and Y (high)
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!macro STAY .ptr {
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sta .ptr
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sty .ptr+1
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}
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; use BIT to swallow the following 1-byte opcode
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!macro HIDE_NEXT_BYTE {
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!byte $24
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}
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; use BIT to swallow the following 2-byte opcode
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!macro HIDE_NEXT_2_BYTES {
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!byte $2C
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}
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