Routines
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E6B6: advance the cursor
Used by the routine at E691.
E6B6 20 B3 E8 JSR $E8B3 test for line increment
E6B9 E6 D3 INC $D3 increment the cursor column
E6BB A5 D5 LDA $D5 get current screen line length
E6BD C5 D3 CMP $D3 compare ?? with the cursor column
E6BF B0 3F BCS $E700 exit if line length >= cursor column
E6C1 C9 4F CMP #$4F compare with max length
E6C3 F0 32 BEQ $E6F7 if at max clear column, back cursor up and do newline
E6C5 AD 92 02 LDA $0292 get the autoscroll flag
E6C8 F0 03 BEQ $E6CD branch if autoscroll on
E6CA 4C 67 E9 JMP $E967 else open space on screen
E6CD A6 D6 LDX $D6 get the cursor row
E6CF E0 19 CPX #$19 compare with max + 1
E6D1 90 07 BCC $E6DA if less than max + 1 go add this row to the current logical line
E6D3 20 EA E8 JSR $E8EA else scroll the screen
E6D6 C6 D6 DEC $D6 decrement the cursor row
E6D8 A6 D6 LDX $D6 get the cursor row
This entry point is used by the routine at E965.
add this row to the current logical line
E6DA 16 D9 ASL $D9,X shift start of line X pointer high byte
E6DC 56 D9 LSR $D9,X shift start of line X pointer high byte back,
make next screen line start of logical line, increment line length and set pointers. clear b7, start of logical line
E6DE E8 INX increment screen row
E6DF B5 D9 LDA $D9,X get start of line X pointer high byte
E6E1 09 80 ORA #%10000000 mark as start of logical line
E6E3 95 D9 STA $D9,X set start of line X pointer high byte
E6E5 CA DEX restore screen row
E6E6 A5 D5 LDA $D5 get current screen line length
add one line length and set the pointers for the start of the line
E6E8 18 CLC clear carry for add
E6E9 69 28 ADC #$28 add one line length
E6EB 85 D5 STA $D5 save current screen line length
This entry point is used by the routine at E591.
E6ED B5 D9 LDA $D9,X get start of line X pointer high byte
E6EF 30 03 BMI $E6F4 exit loop if start of logical line
E6F1 CA DEX else back up one line
E6F2 D0 F9 BNE $E6ED loop if not on first line
E6F4 4C F0 E9 JMP $E9F0 fetch a screen address
E6F7 C6 D6 DEC $D6 decrement the cursor row
E6F9 20 7C E8 JSR $E87C do newline
E6FC A9 00 LDA #$00 clear A
E6FE 85 D3 STA $D3 clear the cursor column
E700 60 RTS
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