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BA8C: unpack memory (AY) into FAC2
Used by the routines at B850, B862, BA28 and BB0F.
BA8C 85 22 STA $22 save pointer low byte
BA8E 84 23 STY $23 save pointer high byte
BA90 A0 04 LDY #$04 5 bytes to get (0-4)
BA92 B1 22 LDA ($22),Y get mantissa 4
BA94 85 6D STA $6D save FAC2 mantissa 4
BA96 88 DEY decrement index
BA97 B1 22 LDA ($22),Y get mantissa 3
BA99 85 6C STA $6C save FAC2 mantissa 3
BA9B 88 DEY decrement index
BA9C B1 22 LDA ($22),Y get mantissa 2
BA9E 85 6B STA $6B save FAC2 mantissa 2
BAA0 88 DEY decrement index
BAA1 B1 22 LDA ($22),Y get mantissa 1 + sign
BAA3 85 6E STA $6E save FAC2 sign (b7)
BAA5 45 66 EOR $66 EOR with FAC1 sign (b7)
BAA7 85 6F STA $6F save sign compare (FAC1 EOR FAC2)
BAA9 A5 6E LDA $6E recover FAC2 sign (b7)
BAAB 09 80 ORA #$80 set 1xxx xxx (set normal bit)
BAAD 85 6A STA $6A save FAC2 mantissa 1
BAAF 88 DEY decrement index
BAB0 B1 22 LDA ($22),Y get exponent byte
BAB2 85 69 STA $69 save FAC2 exponent
BAB4 A5 61 LDA $61 get FAC1 exponent
BAB6 60 RTS
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