added BIOS skeleton

src/zvm_m65/z80_instr_general.s

@@ -4,12 +4,63 @@
 ;
 
 
+Z80_instr_2F:      ; CPL
+
+	lda REG_A
+	eor #$FF
+	sta REG_A
+
+	lda REG_F
+	ora #(Z80_HF + Z80_NF)
+	sta REG_F
+	jmp ZVM_next
+
+; XXX put NEG here
+
+Z80_instr_3F:      ; CCF
+
+	+Z80_PUT_0_NF
+	bbs0 REG_F,@1
+@0:
+	+Z80_PUT_0_HF
+	+Z80_PUT_1_CF
+	jmp ZVM_next
+@1:
+	+Z80_PUT_1_HF
+	+Z80_PUT_0_CF
+	jmp ZVM_next
+
+Z80_instr_37:      ; SCF
+
+	+Z80_PUT_0_HF
+	+Z80_PUT_0_NF
+	+Z80_PUT_1_CF
+	jmp ZVM_next
+
+Z80_instr_76:      ; HALT
+
+	; Used to call BIOS routines
+
+	ldx #$01 ; default BIOS function, warm start
+
+	lda REG_PC
+	sec
+	sbc #$64
+	cmp #33
+	bcs @1
+	tax
+@1:
+	txa
+	asl
+	tax
+	jmp (zvm_BIOS_vectable,x)
+
 Z80_instr_F3:      ; DI
 
 	lda #$00
-	+skip_2_bytes_trash_nvz
-
-	; FALLTROUGH
+	sta REG_IFF1
+	sta REG_IFF2
+	jmp ZVM_next
 
 Z80_instr_FB:      ; EI