ZX Review #5-6 04 ноября 1997

Программирование     Ассемблер

Studies - The procedure for turning the symbol 90 degrees clockwise.

(C) S. Mealing, Tatarstan, Bugulma

 The procedure for turning a character on
 90 degrees clockwise


   This procedure I did for
his editor character set.
140.

        LD HL, ADR; Address Sim, an ox, which is necessary to 
turn 

        LD IX, OBL

        PUSH HL

        PUSH IX

        LD B, 8
LP LD (IX +0), 0

        INC IX

        DJNZ LP

        POP IX

        LD B, 8
LP1 PUSH BC

        PUSH IX

        LD B, 8

        LD A, (HL)
LP2 RLCA

        PUSH AF

        AND 1

        OR (IX +0)

        RRCA

        LD (IX +0), A

        INC IX

        POP AF

        DJNZ LP2

        POP IX

        POP BC

        INC HL

        DJNZ LP1

        PUSH IX

        POP HL

        POP DE

        LD BC, 8

        LDIR

        RET
OBL DEFB 0,0,0,0

        DEFB 0,0,0,0
2

            *