Parted out F_SBC_B to alu_sbc.

1 files changed, 18 insertions, 1 deletions

diff --git a/alu.asm b/alu.asm
index cce4011..18f5260 100644
--- a/alu.asm
+++ b/alu.asm
@@ -1,4 +1,21 @@
 	;; Parting out the big math/logic routines from the
 	;; instruction dispatch table.
 
-	
+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-flag_storage)(a3)
+	move.b	d1,(f_tmp_dst_b-flag_storage)(a3)
+	sub.b	d2,d1
+	move	sr,(f_host_sr-flag_storage)(a3)
+	move.w	#$0202,(flag_byte-flag_storage)(a3)
+	pop.l	d2
+	rts