Routines
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8F80: Divide a signed value by sixteen
Used by the routine at STEER.
Negates a negative, rotates four times and keeps four bits, and puts the sign back. It is how a heading in +$06 and +$07 (up to 32) becomes a movement of two pixels or one.
SCALE_SIGNED 8F80 AND A
8F81 JP P,SCALE_SIGNED_0
8F84 NEG
8F86 RRCA
8F87 RRCA
8F88 RRCA
8F89 RRCA
8F8A AND $0F
8F8C NEG
8F8E RET
SCALE_SIGNED_0 8F8F RRCA
8F90 RRCA
8F91 RRCA
8F92 RRCA
8F93 AND $0F
8F95 RET
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