
 1000  *SAVE S.LOOK FOR PAGE ZERO
 1010  *--------------------------------
 1020  *      SEARCH FOR PAGE ZERO REFERENCES
 1030  *--------------------------------
 1040  MON.A1L    .EQ $3C
 1050  MON.A1H    .EQ $3D
 1060  MON.A2L    .EQ $3E
 1070  MON.A2H    .EQ $3F
 1080  MON.PCL    .EQ $3A
 1090  MON.PCH    .EQ $3B
 1100  *--------------------------------
 1110  KEYBOARD   .EQ $C000
 1120  STROBE     .EQ $C010
 1130  *--------------------------------
 1140  MON.LIST2  .EQ $FE63
 1150  MON.INSDS  .EQ $F88C
 1160  MON.A1PC   .EQ $FE75
 1170  MON.PCADJ  .EQ $F953
 1180  MON.NXTA1  .EQ $FCBA
 1190  *--------------------------------
 1200  *      SET UP CONTROL-Y VECTOR
 1210  *--------------------------------
 1220  SETUPY LDA #$4C     'JMP' OPCODE
 1230         STA $3F8
 1240         LDA #CTRL.Y
 1250         STA $3F9
 1260         LDA /CTRL.Y
 1270         STA $3FA
 1280         RTS
 1290  *--------------------------------
 1300  *      CONTROL-Y COMES HERE
 1310  *--------------------------------
 1320  CTRL.Y
 1330         JSR MON.A1PC IF ADDRESS SPECIFIED, PUT IN PC
 1340  .1     LDY #0
 1350         LDA (MON.PCL),Y
 1360         AND #$0F
 1370         CMP #1
 1380         BEQ .3
 1390         CMP #4
 1400         BCC .6
 1410         BNE .2
 1420         LDA (MON.PCL),Y
 1430         AND #$F0
 1440         CMP #$20     BIT Z
 1450         BEQ .3
 1460         CMP #$80
 1470         BCC .6       NO
 1480         CMP #$D0
 1490         BEQ .6       NO
 1500         CMP #$F0
 1510         BEQ .6       NO
 1520         BNE .3       YES
 1530  .2     CMP #7
 1540         BCS .6
 1550  *--------------------------------
 1560  *      INSTRUCTION REFERENCES PAGE-ZERO
 1570  *--------------------------------
 1580  .3     LDA #1       DISASSEMBLE THIS ONE INSTRUCTION
 1590         JSR MON.LIST2   DISASSEMBLE
 1600         LDA KEYBOARD    SEE IF KEYPRESS
 1610         BPL .7       NO
 1620         STA STROBE   YES, CLEAR IT
 1630         CMP #$8D
 1640         BEQ .5
 1650  .4     LDA KEYBOARD
 1660         BPL .4
 1670         STA STROBE
 1680         CMP #$8D
 1690         BNE .7
 1700  .5     RTS
 1710  *--------------------------------
 1720  *      DOES NOT REFERENCE PAGE-ZERO
 1730  *--------------------------------
 1740  .6     LDX #0
 1750         JSR MON.INSDS    GET LENGTH OF INSTRUCTION
 1760         JSR MON.PCADJ
 1770         STA MON.PCL
 1780         STY MON.PCH
 1790  *--------------------------------
 1800  *      TEST IF FINISHED
 1810  *--------------------------------
 1820  .7     LDA MON.PCL
 1830         CMP MON.A2L
 1840         LDA MON.PCH
 1850         SBC MON.A2H
 1860         BCC .1
 1870         RTS

