diff options
| -rw-r--r-- | alu.asm | 18 | ||||
| -rw-r--r-- | opcodes.asm | 13 |
2 files changed, 22 insertions, 9 deletions
@@ -19,3 +19,21 @@ alu_sbc: move.w #$0202,(flag_byte-flag_storage)(a3) 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-flag_storage)(a3) + move.b d1,(f_tmp_dst_b-flag_storage)(a3) + move.b #1,(f_tmp_byte-flag_storage)(a3) + andi.b #%00000010,(flag_valid-flag_storage)(a3) + move.b #%00000010,(flag_byte-flag_storage)(a3) + sub d0,d1 + move sr,(f_host_sr-flag_storage)(a3) + rts diff --git a/opcodes.asm b/opcodes.asm index 35a7f4f..fca259c 100644 --- a/opcodes.asm +++ b/opcodes.asm @@ -1368,15 +1368,10 @@ emu_op_8f: ;; Do a SUB \2,\1 ;; XXX CHECK F_SUB_B MACRO ; 22 bytes? - ;; XXX use lea and then d(an) if you have a spare register. - ;; preserve operands for flagging - move.b \1,(f_tmp_src_b-flag_storage)(a3) - move.b \2,(f_tmp_dst_b-flag_storage)(a3) - move.b #1,(f_tmp_byte-flag_storage)(a3) - andi.b #%00000010,(flag_valid-flag_storage)(a3) - move.b #%00000010,(flag_byte-flag_storage)(a3) - sub \1,\2 - move sr,(f_host_sr-flag_storage)(a3) + move.b \2,d1 + move.b \1,d0 + bsr alu_sub + move.b d1,\2 ENDM START |