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48 lines
1.0 KiB
Lua
48 lines
1.0 KiB
Lua
%import c64lib
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%import c64utils
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%import c64flt
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%zeropage basicsafe
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%option enable_floats
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; TODO: fix register argument clobbering when calling asmsubs.
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; for instance if the first arg goes into Y, and the second in A,
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; but when calculating the second argument clobbers Y, the first argument gets destroyed.
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main {
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sub start() {
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function(20, calculate())
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asmfunction(20, calculate())
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c64.CHROUT('\n')
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if @($0400)==@($0402) and @($0401) == @($0403) {
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c64scr.print("ok: results are same\n")
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} else {
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c64scr.print("error: result differ; arg got clobbered\n")
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}
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}
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sub function(ubyte a1, ubyte a2) {
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; non-asm function passes via stack, this is ok
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@($0400) = a1
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@($0401) = a2
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}
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asmsub asmfunction(ubyte a1 @ Y, ubyte a2 @ A) {
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; asm-function passes via registers, risk of clobbering
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%asm {{
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sty $0402
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sta $0403
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}}
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}
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sub calculate() -> ubyte {
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Y = 99
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return Y
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}
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}
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