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|| -*- gas -*-
|| Parting out the big math/logic routines from the
|| instruction dispatch table.
.text
alu_add:
|| ADD instruction
|| ADD d1,d0
|| d1 + d0 -> d1
move.b d0,f_tmp_src_b | preserve operands for flag work
move.b d1,f_tmp_dst_b
move.b #1,f_tmp_byte
add d0,d1
move sr,f_host_sr
move.w #0202,flag_byte
rts
alu_adc:
|| ADC instruction
|| ADC d1,d0
|| d1 + d0 + carry -> d1
bsr flags_normalize
move.b flag_byte(pc),d2
andi.b #1,d2
add.b d0,d2
move.b d2,f_tmp_src_b
move.b d1,f_tmp_dst_b
add.b d2,d1
move sr,f_host_ccr
move.w #$0202,flag_byte
rts
alu_sbc:
|| SBC instruction
|| SBC d1,d0
|| d1 - (d0+C) -> d1
|| sets flags
push.l d2
bsr flags_normalize
move.b flag_byte(pc),d2
andi.b #1,d2
add.b d0,d2
move.b d2,f_tmp_src_b
move.b d1,f_tmp_dst_b
sub.b d2,d1
move sr,f_host_sr
move.b #$02,flag_byte
move.b #$02,flag_valid
pop.l d2
rts
alu_sub:
|| SUB instruction
|| SUB d1,d0
|| d1 - d0 -> d1
|| sets flags
|| XXX use lea and then d(an) if you have a spare register.
|| preserve operands for flagging
move.b d0,f_tmp_src_b
move.b d1,f_tmp_dst_b
move.b #1,f_tmp_byte
andi.b #%00000010,flag_valid
move.b #%00000010,flag_byte
sub d0,d1
move sr,f_host_sr
rts
alu_and:
|| XXX do this
rts
alu_xor:
|| XXX do this
rts
alu_or:
|| XXX do this
rts
alu_cp:
|| Same as SUB but the macro that calls this doesn't save the
|| result.
|| SPEED can hardcode one of the arguments to always be the A register.
move.b d0,f_tmp_src_b
move.b d1,f_tmp_dst_b
move.b #1,f_tmp_byte
andi.b #%00000010,flag_valid
move.b #%00000010,flag_byte
sub.b d0,d1
move sr,f_host_sr
rts
|
