26 lines
533 B
ArmAsm
26 lines
533 B
ArmAsm
// #LAYOUT# STD * #TAKE
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// #LAYOUT# X16 BASIC_0 #TAKE-OFFSET 2000
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// #LAYOUT# * BASIC_0 #TAKE
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// #LAYOUT# * * #IGNORE
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//
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// Math package - subtract FAC1 from FAC2
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//
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// See also:
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// - [CM64] Computes Mapping the Commodore 64 - page 112
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// - https://www.c64-wiki.com/wiki/Floating_point_arithmetic
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// - https://codebase64.org/doku.php?id=base:kernal_floating_point_mathematics
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//
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// XXX test this
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sub_FAC2_FAC1:
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// Toggle FAC1 sign
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lda FAC1_sign
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eor #$FF
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sta FAC1_sign
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// Perform addition
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jmp add_FAC2_FAC1
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