A2osX/FSE/FSE.S.STB80.txt

NEW
  AUTO 3,1
*--------------------------------
C.TMP1 .EQ VAR.BEG-1
C.TMP2 .EQ C.TMP1-1
C.TMP3 .EQ C.TMP2-1
C.TMP4 .EQ C.TMP3-1
  .DO C.TMP4<$300
  *** VARS<$300
  .FIN
*--------------------------------
* STANDARD VIDEO JUMP VECTORS
*  1. READ KEYBOARD KEY CODE
*       TURNS ON CURSOR
*       GETS KEY CODE
*       TURNS OFF CURSOR
*       REG-A HAS KEY CODE SIGN BIT ON.
*  2. HORIZONTAL TAB
*       REG-A HAS TAB 0-79
*  3. VERTICAL TAB
*       REG-A HAS TAB 0-23
*  4. CLEAR TO END OF LINE
*  5. CLEAR TO END OF SCREEN
*  6. CHARACTER OUTPUT ROUTINE
*       REG-A HAS CHAR TO OUTPUT.
*       MUST NOT SCROLL SCREEN OR
*       GO TO NEXT LINE WHEN LAST
*       CHARACTER IS PRINTED ON A LINE.
*--------------------------------
       JMP C.RD.KBD
       JMP C.MY.HTAB
       JMP C.MY.VTAB
       JMP C.MY.CLREOL
       JMP C.MY.CLREOP
       JMP C.MY.COUT
*--------------------------------
C.MY.CLP LDA CTR
       JSR C.MY.VTAB
C.MY.CLREOP JSR C.MY.CLREOL       CLEAR TO END OF LINE
       LDA #0            START COL 0 FOR NEXT LINE
       JSR C.MY.HTAB
       INC CTR           BUMP TO NEXT LINE
       LDA CTR
       CMP LAST.LINE     CHK FOR END
       BCC C.MY.CLP      < END
       BEQ C.MY.CLP      = END
       RTS               > END
*--------------------------------
C.MY.HTAB STA C.STB.COL  SET HORIZ. POSN
       LSR
       STA CH            CH = POSN/2
       RTS
*--------------------------------
C.MY.VTAB STA CV         SET VERT POSN
       RTS
*--------------------------------
C.MY.COUT STY C.TMP1     SAVE Y REG
       AND #$7F          MASK OFF HIGH BIT
       PHA
       LDA CV            GET VERT POSN
       CLC
       ADC C.STB.TOPADR
       LDY #18
       STY C.CRTC        CRTC = REG 18
       STA C.CRTC+1      SET LINE POSN
       LDA C.STB.COL
       INY
       STY C.CRTC        CRTC = REG 19
       STA C.CRTC+1      SET COL POSN
       LDA C.STB.TOPADR
       LDY #12
       STY C.CRTC        CRTC = REG 12
       STA C.CRTC+1      SET SCROLL POSN
       LDY #$1F
       STY C.CRTC        POINT TO DUMMY REG
       PLA
       CMP #$20
       BCS .1            NON CONTROL CHAR
       ORA #$C0          SET INV BIT, MAKE LETR
.1     BIT C.CRTC        WAIT FOR RIGHT TIME
       BPL .1
       STA C.CRTC+3      PUT CHAR IN LATCH
       INC C.STB.COL     NEXT COLUMN
       LDY C.TMP1        RESTORE Y REG
       RTS
*--------------------------------
C.MY.CLREOL STY C.TMP3   SAVE Y REG
       STX C.TMP4        SAVE X REG
.1     LDY C.STB.COL     GET COL POSN
       CPY SCREEN.WIDTH  END OF LINE
       BCS .2            YES
       LDA #$A0          A REG = BLANK
       JSR C.MY.COUT     PRINT IT
       JMP .1            NEXT COLUMN
.2     LDY C.TMP3        RESTORE Y REG
       LDX C.TMP4        RESTORE X REG
       RTS
*--------------------------------
* STB80 IO ROUTINES
*--------------------------------
C.CRTC   .EQ $C0B0       CRT CONTROLLER CHIP
C.STB.TOPADR .EQ $57B    SCROLL LINE START
C.STB.COL    .EQ $5FB    COLUMN POSN
*--------------------------------
C.RD.KBD JSR C.CURSOR.ON TURN ON CURSOR
.1     LDA $C000         WAIT FOR KEY
       BPL .1
       BIT $C010         STROBE KBD TO KILL FLAG BIT
       PHA               SAVE CHAR
       JSR C.CURSOR.OFF  TURN OFF CURSOR
       PLA               RESTORE CHAR
       RTS
*--------------------------------
C.CURSOR.ON LDA POSV     POSITION VERTICALLY
       JSR C.MY.VTAB
       LDA POSH
       SEC
       SBC LEFT.MARGIN
       CLC
       ADC RM.ADJUST
       JSR C.MY.HTAB     POSITION HORIZONTALLY
       LDA ESC.FLAG      TEST ESC MODE
       BEQ .1            IT IS IN SCROLL MODE
       LDA #$67          EDIT MODE GETS LITTLE CURSOR
       BNE .2            ...ALWAYS
.1     LDA #$C0          SCROLL MODE GETS NORMAL CURSOR
.2     PHA
       LDA #$0A
       STA C.CRTC        CTRC = REG 10
       PLA
       STA C.CRTC+1      SET CURSOR START DATA
C.WRIT LDA #$0F
       STA C.CRTC        CTRC = REG 15
       LDA C.STB.COL
       STA C.CRTC+1      SET CURSOR COLUMN POSN
       LDA #$0E
       STA C.CRTC        CRTC = REG 14
       LDA CV
       CLC
       ADC C.STB.TOPADR
       STA C.CRTC+1      SET CURSOR LINE POSN
       RTS
*--------------------------------
C.CURSOR.OFF LDA #24     LINE 24 IS NON DISPLAYABLE
       JSR C.MY.VTAB     TAB TO THERE
       JMP C.WRIT        AND POSN CURSOR THERE
*--------------------------------
MAN
SAVE usr/src/fse/fse.s.stb80
LOAD usr/src/fse/fse.s
ASM