23 lines
432 B
ArmAsm
23 lines
432 B
ArmAsm
// #LAYOUT# STD * #TAKE
|
|
// #LAYOUT# * BASIC_0 #TAKE
|
|
// #LAYOUT# * * #IGNORE
|
|
|
|
//
|
|
// Math package - toggle FAC1 sign (if not 0)
|
|
//
|
|
// See also:
|
|
// - [CM64] Computes Mapping the Commodore 64 - page 117
|
|
// - https://www.c64-wiki.com/wiki/Floating_point_arithmetic
|
|
//
|
|
|
|
NEGOP:
|
|
|
|
lda FAC1_exponent
|
|
beq !+ // do not toggle the sign if value is 0
|
|
|
|
lda FAC1_sign
|
|
eor #$FF
|
|
sta FAC1_sign
|
|
!:
|
|
rts
|