Subversion Repositories pentevo

                ifndef  __st6instrinc
__st6instrinc   equ     1

;****************************************************************************
;*                                                                          *
;*   AS 1.42 - File INSTR.INC                                               *
;*                                                                          *
;*   contains macros for some commonly missing instructions on ST6          *
;*                                                                          *
;****************************************************************************

; Add/Subtract with Carry: first operand must be A (accumulator)

adc             macro   dst,src
                jrnc    NoCarry
                inc     dst
NoCarry:        add     dst,src         ; Rest normal addieren
                endm

sbc             macro   dst,src
                jrnc    NoCarry
                dec     dst
NoCarry:        sub     dst,src
                endm

; OR operator:
; uses De Morgan's rule: A OR B = /((/A) AND (/B))
; uses W register
; dst must be A (accumulator)

or              macro   dst,src
                com     dst
                ld      w,dst
                ld      dst,src
                com     dst
                and     dst,w
                com     dst
                endm

; XOR Operator:
; uses the principle of four NAND gates, i.e. does not have to use the OR macro
; uses V and W register
; dst must be A (accumulator)

xor             macro   dst,src
                ld      v,dst           ; Op1 retten
                and     dst,src         ; Hilfsergebnis A NAND B bilden
                com     dst
                ld      w,dst           ; in W retten
                ld      dst,v           ; Op1 nochmal holen
                and     dst,w           ; 1. Teilergebnis A NAND W bilden
                com     dst
                ld      v,dst           ; in V retten
                ld      dst,src         ; 2. Teilergebnis B NAND W bilden
                and     dst,w
                com     dst
                and     dst,v
                com     dst
                endif
                endm

; rotate right with carry
; fairly brute force, I did not have any better idea...
; dst must be A (accumulator)

rrc             macro   dst
                rept    7
                 rlc    dst
                endm
                endm

;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
; For those missing the ROMWIN statement:

romwin          macro   adr
                assume  rombase:adr>>6
                endm

                endif                   ; __st6instrinc