- Implemented support for Sux's base extension.

  This is the biggest milestone I've reached for this
  project, since the base extension changes alot about
  what Sux can do by default, and now makes it a viable
  instruction set for modern day use, when compared
  with other instruction sets.

2 files changed, 1266 insertions, 0 deletions

diff --git a/programs/sub-suite/print_char.s b/programs/sub-suite/print_char.s
new file mode 100644
index 0000000..e12461c
--- /dev/null
+++ b/programs/sub-suite/print_char.s
@@ -0,0 +1,147 @@
+print_char:
+;	sta a		; Save the typed character for now.
+	pha		; Preserve the character.
+;	ldb #2		; Make sure that set_ptr sets the third pointer.
+	lda.d #buffer	; Set the third pointer to the start of the screen buffer.
+	pha.q		; Push the pointer onto the stack.
+	lda sp+9	; Get the character back.
+;	jsr set_ptr	;
+;	ldb #0		; Set B to zero.
+;	tba		; Set the Accumulator to zero.
+;	lda a		; Get back the character.
+	cmp #$1B	; Did the user type an escape character?
+	beq esc		; Yes, so go check the escape code.
+	cmp #'\n'	; No, but did the user type a newline?
+	beq nl		; Yes, so handle the newline.
+	cmp #$C		; No, but did the user type Ctrl+L?
+	beq clr_scr	; Yes, so clear the screen.
+	cmp #19		; No, but did the user type Ctrl+S?
+	beq en_step	; Yes, so enable clock/instruction stepping.
+	cmp #18		; No, but did the user type Ctrl+R?
+	beq dis_step	; Yes, so disable clock/instruction stepping.
+	cmp #'\b'	; No, but did the user type a backspace?
+	beq bs		; Yes, so handle the backspace.
+	cmp #$7F	; No, but did they type Delete?
+	beq bs		; Yes, so treat it as a backspace.
+printc:
+	lda #0		; No, so start trying to print a character.
+	sta d		;
+	lda (sp+1), y	; Are we at the end of the string?
+	beq @save	; Yes, so just print the character.
+	lda b		; No, but was the flag set?
+	bne @save	; Yes, so don't shift the line.
+	sty.w scr_ptr	; No, so save the cursor index for later.
+	jsr fndend	; Find the end of the line.
+	bra @shift	; Start shifting the line right.
+@update:
+	lda scr_col	; Save the current column position for later.
+	sta scr_tcol	;
+@update1:
+	jsr findend	; Find the end of the line.
+	sta e		; Use it for redrawing the line.
+	sta scr_row	; Set the row position to to the end of the line.
+	jsr findst	; Find the start of the line.
+	lda scr_row	; Get the start of the line.
+@update2:
+	sta f		; Set the starting line, to the start of the line.
+	jsr rdrw_ln	; Redraw the line.
+	lda scr_trow	; Get the real row position back.
+	sta scr_row	;
+	lda scr_tcol	; Get the real column position back.
+	sta scr_col	;
+	jsr update_pos	; Update the cursor's position.
+	dec d		;
+	bra @save1	;
+@shift:
+	ldy.w scr_ptr3	;
+	inc scr_ptr3	;
+	tyx		;
+	dey		;
+	ldb #1		;
+	stb d		;
+	jsr shftln	;
+	ldb #1		;
+	stb d		;
+;	lda a		;
+	lda sp+9	;
+	sta (sp+1), y	; store typed character into the input buffer.
+	lda scr_row	;
+	sta scr_trow	;
+	bra @update	;
+@save:
+	ldb d		;
+	bne @update	;
+@save1:
+;	lda a		;
+	lda sp+9	;
+	sta (sp+1), y	; store typed character into the input buffer.
+@incr:
+	inc scr_col	; Increment the cursor's x coordinate.
+	iny		;
+@wrapped:
+	ldb #1		;
+	stb f		;
+	ldb scr_col	;
+	cpb #maxcol+1	;
+	bcs @scrolled	;
+@print:
+	sta scr		; Echo typed character.
+	ldb f		;
+	beq @wrap	;
+	bra printc_end	;
+@scrolled:
+	ldb scr_row	;
+	cpb #maxrow	;
+	bcs @scroll	;
+@wrapped2:
+	ldb #0		;
+	stb f		;
+	bra @print	;
+@scroll:
+	sta scr		; Echo typed character.
+	clc		;
+	lda #1		;
+	sta wrapped	;
+	jsr scrl_down	;
+@wrap:
+	ldb #0
+	stb scr_col	;
+	ldb scr_row	;
+	cpb #maxrow	;
+	bcs @wrap2	;
+@wrap1:
+	inc scr_row	;
+@wrap2:
+	phx.w		;
+	clc		;
+	lda scr_row	;
+	adc scr_str	;
+	tax		;
+	jsr setbit	;
+	plx.w		;
+	jsr update_pos	;
+printc_end:
+	pla.q		; Pull the pointer off the stack.
+	pla		; Pull the character off the stack.
+	and #0		; Reset A.
+	rts		;
+
+nl:
+	lda #0		; Reset A.
+	ldb (sp+1), y	; Is this character not a null terminator?
+	bne @scroll	; Yes, so don't overwrite it.
+	sta (sp+1), y	; No, so overwrite it.
+@scroll:
+	sta scr_col	; Move the cursor to the start of the next line.
+	lda scr_row	; Get the row position.
+	cmp #maxrow	; Are we at the bottom of the screen?
+	bcc @incr	; No, so move down one line.
+	jsr scrl_down	; Yes, so scroll down one line.
+	bra @end	; We are done.
+@incr:
+	inc scr_row	; Move the cursor down by one line.
+	jsr update_pos	; Update the cursor's position.
+@end:
+	lda #'\n'	; Print the newline.
+	sta a		;
+	rts		;
diff --git a/programs/sub-suite/subeditor-new.s b/programs/sub-suite/subeditor-new.s
new file mode 100644
index 0000000..6c1cfb1
--- /dev/null
+++ b/programs/sub-suite/subeditor-new.s
@@ -0,0 +1,1119 @@
+; SuBEditor.
+;
+; Writen in Sux assembly by
+; mr b0nk 500 <b0nk@b0nk.xyz>
+
+
+.org $8000
+reset:
+	cps		; Reset the processor status register.
+	ldx.w #$FFFF	; Reset the stack pointer.
+	txs		;
+	ldy #0		; Reset the Y register.
+	sty end		;
+	tyx		; Reset the X register.
+	lda #maxrow	; Set the end of the screen to the screen's max row count.
+	sta scr_end	;
+	tya		; Reset the Accumulator.
+	sta scr_str	; Set the start of the screen back to zero.
+	sta.q bitabl	; Reset the first half of the linewrap table.
+	sta.q bitabl+8	; Reset the second half of the linewrap table.
+	inc end		;
+	lda.w #$1FFF	; Set the clear count to $1FFF.
+	pha.w		; Push the clear count to the stack.
+	lda.d #buffer	; Set the array to be cleared to the screen buffer.
+	pha.q		; Push it on to the stack.
+	jsr clr_arr	; Clear the screen buffer.
+	pla.q		; Pull the pointer off of the stack.
+	pla.w		; Pull the clear count off of the stack.
+	and #0		; Reset A.
+	jsr pnt_strt	; Print the starting message.
+	lda #$C		; Clear the screen.
+	sta scr		;
+	bra start	; Goto the start of the main program.
+
+clr_arr:
+	phb 		; Preserve whatever was in B.
+	ldb #0		; Clear B.
+	clc		; Prepare for a non carrying add.
+	adc #8		; Set the second pointer to the parameter, plus eight.
+	pha.q		; Push it onto the stack.
+	tba		;
+@loop:
+	cpy.w sp+26	; Did we clear all of the array?
+	bcs @end	; Yes, so we're done.
+	sta.q (sp+18), y; No, so clear eight bytes.
+	sta.q (sp+1), y	; Clear eight more bytes.
+	tya		; Copy the array index.
+	adc #$10	; Increment the index by 16.
+	tay		; Update the index.
+	tba		; Reset the Accumulator.
+	sta.q (sp+18), y; Do this one more time, to clear 32 bytes.
+	sta.q (sp+1), y	;
+	tya		;
+	adc #$10	;
+	tay		;
+	tba		;
+	bra @loop	; Keep looping.
+@end:
+	ldy.w zero	; Set the index back to zero.
+	pla.q		; Move the stack pointer back.
+	tba		; Reset A.
+	plb 		; Get whatever was in the B register, back.
+	rts		; End of clr_arr.
+
+pnt_strt:
+	lda.w #ed_name	; Print the name of the editor.
+	jsr print_str	;
+	lda.w #ver_str	; Print the version text.
+	jsr print_str	;
+	lda.w #ed_ver	; Print the version number.
+	jsr print_str	;
+	lda.w #ed_sver	; Print the sub version number.
+	jsr print_str	;
+	lda #'\n'	; Print a newline.
+	jsr print_char	;
+	lda.w #made	; Print the "Created by" text.
+	jsr print_str	;
+	lda.w #author	; Print the name of the author.
+	jsr print_str	;
+	lda #'\n'	; Print a newline.
+	jsr print_char	;
+	rts		; End of pnt_strt.
+
+start:
+	lda #0		; TODO: Update this for the Super VIA.
+	sta status	; Clear the control register of the I/O adapter.
+	tax		; Reset X.
+	phy.w		; Save the cursor index for later.
+	tay		; Reset the cursor index.
+	lda.w #$3FF	; Set the clear count to $3FF.
+	pha.w		; Push the clear count onto the stack.
+	lda.d #cmd_buf	; Set the array to be cleared to the command buffer.
+	pha.q		; Push the pointer onto the stack.
+	jsr clr_arr	; Clear the command buffer.
+	pla.q		; Pull the pointer off of the stack.
+	pla.w		; Pull the clear count off of the stack.
+	ply.w		; Get back the cursor index.
+	and #0		; Reset the Accumulator.
+	sta end		;
+	bra read	; Start reading the keyboard.
+
+read:
+	lda #0		; Reset the Accumulator.
+	sta end		; Disable the dummy flag.
+	inc end		; Enable the dummy flag.
+	lda status	; Did we get a key?
+	beq read	; No, so try again.
+	jsr getchar	; Yes, and was it a newline?
+	beq parse	; Yes, so start parsing the line.
+	bra read	; No, so keep looping.
+
+parse:
+	lda #0		;
+	tax		;
+	jsr subasm	;
+	bra start	;
+
+
+print_str:
+	ldx #0		; Reset X.
+	pha.q		; Push the parameter onto the stack.
+@loop:
+	ldb #1		; Enable replace mode.
+	stb b		;
+	and #0		; No, reset the accumulator.
+	phy.w		; Save the cursor index.
+	txy		; Copy the string index into Y.
+	lda (sp+3), y	; Are we at the end of the string?
+	ply.w		; Get the cursor index back.
+	beq @end	; Yes, so we're done.
+	inx             ; No, so increment the string index.
+	jsr print_char	; Print the character.
+	bra @loop	; Keep looping.
+@end:
+	pla.q		; Pull the parameter off the stack.
+	ldb #0		; Enable insert mode.
+	stb b		;
+	tba		; Reset A.
+	rts		; End of print_str.
+
+getbit:
+	clc		; Clear the carry flag.
+	lda scr_str	; Has the screen been scrolled?
+	bne getbt0	; Yes, so add the screen offset to the current line number.
+	ldx scr_row	; No, so just use the current line number.
+	bra getbt1	; Start getting the bit.
+getbt0:
+	lda scr_row	; Get the current line number.
+	adc scr_str	; Add the screen offset to it.
+	tax		; Use it as the wrap index.
+getbt1:
+	tab		; Save the parameter.
+	lda.d #bitabl	; Set the second pointer to the linewrap table.
+	pha.q		; Push the pointer onto the stack.
+	tba		; Get the parameter back.
+	jsr bitpos	; Get the bit, and byte position.
+	phy.w		; Save the screen index.
+	txy		; Get the byte position.
+	ldb (sp+3), y	; Get one byte of the wrap table.
+	ply.w		; Get the screen index back.
+	aba		; Mask out the bit of the current line number.
+	cmp #1		; Set the carry flag, if true.
+	bra bitout	; We are done.
+
+clrbit:
+	tab		; Save the parameter.
+	lda.d #bitabl	; Set the second pointer to the linewrap table.
+	pha.q		; Push the pointer onto the stack.
+	tba		; Get the parameter back.
+	jsr bitpos	; Get the bit, and byte position.
+	xor #$FF	; Invert the bitmask.
+	phy.w		; Save the screen index.
+	txy		; Get the byte position.
+	ldb (sp+3), y	; Get one byte of the wrap table.
+	aba		; Clear the bit of the current line number.
+bitsav:
+	sta (sp+3), y	; Update the wrap table.
+	ply.w		; Get the screen index back.
+bitout:
+	pla.q		; Pull the pointer off the stack.
+	and #0		; Reset A.
+	ldx bitmask	; Return the bitmask.
+	rts		; We are done.
+
+setbit:
+	tab		; Save the parameter.
+	lda.d #bitabl	; Set the second pointer to the linewrap table.
+	pha.q		; Push the pointer onto the stack.
+	tba		; Get the parameter back.
+	jsr bitpos	; Get the bit, and byte position.
+	phy.w		; Save the screen index.
+	txy		; Get the byte position.
+	ldb (sp+3), y	; Get one byte of the wrap table.
+	oab		; Set the bit of the current line number.
+	bra bitsav	; Save the bit.
+
+bitpos:
+	tab		; Save the parameter.
+	lda.w #bits	; Set the first pointer to the bitmask table.
+	pha.q		; Push the pointer onto the stack.
+	tba		; Get the parameter back.
+	stx bitmask	; Make the line number the bitmask.
+	txa		; Copy it to the Accumulator.
+	and #7		; Get the bit position.
+	phy.w		; Save the cursor index.
+	tay		; Use the bit position as the index.
+	tax		; Copy it into X.
+	lda (sp+3), y	; Get the bitmask.
+	ply.w		; Get back the cursor index.
+	pha 		; Save the bitmask.
+	lda bitmask	; Get the line number.
+	lsr #3		; Get the byte position.
+	tax		; Copy it into X.
+	pla 		; Get back the bitmask.
+	tab		; Preserve the bitmask.
+	pla.q		; Pull the pointer off the stack.
+	tba		; Get the bitmask back.
+	rts		; End of bitpos.
+
+getchar:
+	lda kbd		; Get the character that was typed from the keyboard.
+	ldb #0		; Reset the B register.
+	stb e		; Set the temporary row position to zero, in case we get a newline.
+	stb b		; Enable insert mode.
+	pha 		; Save the character.
+	phy.w		; Save the cursor index.
+	cmp #'\n'	; Was the character that was typed, a newline?
+	bne @print	; No, so just print the character.
+	jsr cmd_cpy	; Yes, so start copying the line to the command buffer.
+@print:
+	ply.w		; Get back the cursor index.
+	pla 		; Get back the character.
+	ldb e		; Is the temporary row position non zero?
+	bne @row	; Yes, so reset the row positon.
+@print1:
+	jsr print_char	; No, so print the character.
+	lda a		; Get the return value.
+	cmp #'\n'	; Is the return value, a newline?
+	beq @true	; Yes, so return true.
+	bra @false	; No, so return false.
+@row:
+	ldb e		; Get the temporary row position.
+	cpb #maxrow	; Is temporary row position, at, or above the bottom of the screen?
+	beq @row2	; Yes, so leave it as is.
+	bcs @row1	; No, so set it to the bottom of the screen.
+	bra @row2	; Yes, so leave it as is.
+@row1:
+	ldb #maxrow	; Set the row position to the bottom of the screen.
+@row2:
+	stb scr_row	; Set the row position.
+	bra @print1	; Print the character.
+@true:
+	lda #0		; Return true.
+	bra @end	; We are done.
+@false:
+	lda #1		; Return false.
+@end:
+	rts		; End of getchar.
+
+
+cmd_cpy:
+	lda scr_row	; Get the row position.
+	sta scr_trow	; Save it for later.
+	jsr findend	; Find the end of the line.
+	ldb scr_str	; Has the screen been scrolled?
+	beq @start	; No, so don't subtract the screen's starting point from the line number.
+@offset:
+	sec		; Yes, so make sure that we don't subtract by the starting point, plus one.
+	sbc scr_str	; Offset the row position, back by the screen's starting point.
+	clc		; Clear the carry flag, so that nothing odd occurs.
+@start:
+	sta scr_row	; Set the row position to the end of the line.
+	sta e		; Save it into the temporary row posiition.
+	jsr findst	; Find the start of the line.
+	clc		; Clear the carry flag.
+	lda scr_row	; Get the row position.
+	adc scr_str	; Add it with the screen's starting row.
+	mul #maxcol+1	; Multiply it with the width of the screen, plus one.
+	tay		; Place it into the index.
+	ldx.w #0	; Reset the X register.
+	ldb #0		; Make sure that set_ptr sets the first pointer.
+	lda.d #buffer	; Set the first pointer to the start of the screen buffer.
+	pha.q		; Push the pointer onto the stack.
+	lda.d #cmd_buf	; Set the second pointer to the start of the command buffer.
+	pha.q		; Push the pointer onto the stack.
+	tba		; Set the accumulator to zero.
+@loop:
+	ldb #0		; Reset the B register.
+	lda.q (sp+9), y	; Get eight bytes from the current line.
+@loop1:
+	phy.w		; Save the screen index.
+	txy		; Get the command buffer index.
+	sta (sp+3), y	; Copy one byte from the screen buffer, to the command buffer.
+	inx		; Increment the command buffer index.
+	ply.w		; Get back the screen index.
+	cpx.w #$3FF	; Are we at the end of the command buffer?
+	bcs @end	; Yes, so we're done.
+	iny		; No, so increment the screen index.
+	inb		; Increment the byte count.
+	lsr #8		; Shift in the next byte.
+	stb g		; Save the byte count.
+	tab		; Save the string buffer.
+	and #$FF	; Is this byte of the buffer, a null terminator?
+	beq @end1	; Yes, so we're done.
+	tba		; No so get back the string buffer.
+	ldb g		; Get back the byte count.
+	cpb #7		; Did we shift in eight bytes?
+	beq @loop	; Yes, so get eight more bytes.
+	bra @loop1	; No, so keep shifting in more bytes.
+@end:
+	ldb #0		; Reset B.
+	phy.w		; Save the screen index.
+	txy		; Get the command buffer index.
+	stb (sp+3), y	; Terminate the command buffer.
+	ply.w		; Get back the screen index.
+@end1:
+	pla.q		; Pull one of the pointers off the stack.
+	pla.q		; Pull the other pointer off the stack.
+	tba		; The B register is zero, so clear the Accumulator.
+	rts		; End of cmd_cpy.
+
+
+findst:
+	lda #0		; Reset A.
+@loop:
+	pha 		; Save the current line number.
+	jsr getbit	; Is this the start of the line?
+	pla 		; Get the current line number back.
+	bcc @end	; Yes, so we're done.
+	inc		; No, so check the next physical line.
+	dec scr_row	; Are we at the top of the screen?
+	bpo @loop	; No, so keep looping.
+	dec		; Yes, so move back one line.
+	inc scr_row	; Put the row postiion back to zero.
+@end:
+	cmp #0		; Update all the flags.
+	rts		; End of findst.
+
+
+fndend:
+	lda.d #buffer	; Set the first pointer to the start of the screen buffer.
+	pha.q		; Push the pointer onto the stack.
+	phb 		; Save the contents of the B register.
+	ldb #0		; Make sure that set_ptr sets the first pointer.
+	tba		; Set the Accumulator to zero.
+	plb 		; Restore the contents of the B register.
+	phy.w		;
+@loop:
+	lda (sp+3), y	; Are we at the end of the string?
+	beq @end	; Yes, so we're done.
+	iny		; No, so increment the cursor index.
+	bra @loop	; Keep looping.
+@end:
+	sty.w scr_ptr3	;
+	ply.w		;
+	pla.q		; Pull the pointer off the stack.
+	and #0		; Reset A.
+	rts		; End of fndend.
+
+findend:
+	jsr fndend	;
+	lda.w scr_ptr3	;
+	div #maxcol+1	;
+	rts		;
+
+
+print_char:
+	sta a		; Save the typed character for now.
+	ldb #2		; Make sure that set_ptr sets the third pointer.
+	lda.d #buffer	; Set the third pointer to the start of the screen buffer.
+	jsr set_ptr	;
+	ldb #0		; Set B to zero.
+	tba		; Set the Accumulator to zero.
+	lda a		; Get back the character.
+	cmp #$1B	; Did the user type an escape character?
+	beq esc		; Yes, so go check the escape code.
+	cmp #'\n'	; No, but did the user type a newline?
+	beq nl		; Yes, so handle the newline.
+	cmp #$C		; No, but did the user type Ctrl+L?
+	beq clr_scr	; Yes, so clear the screen.
+	cmp #19		; No, but did the user type Ctrl+S?
+	beq en_step	; Yes, so enable clock/instruction stepping.
+	cmp #18		; No, but did the user type Ctrl+R?
+	beq dis_step	; Yes, so disable clock/instruction stepping.
+	cmp #'\b'	; No, but did the user type a backspace?
+	beq bs		; Yes, so handle the backspace.
+	cmp #$7F	; No, but did they type Delete?
+	beq bs		; Yes, so treat it as a backspace.
+printc:
+	lda #0		; No, so start trying to print a character.
+	sta d		;
+	lda (ptr3), y	; Are we at the end of the string?
+	beq @save	; Yes, so just print the character.
+	lda b		; No, but was the flag set?
+	bne @save	; Yes, so don't shift the line.
+	sty.w scr_ptr	; No, so save the cursor index for later.
+	jsr fndend	; Find the end of the line.
+	bra @shift	; Start shifting the line right.
+@update:
+	lda scr_col	; Save the current column position for later.
+	sta scr_tcol	;
+@update1:
+	jsr findend	; Find the end of the line.
+	sta e		; Use it for redrawing the line.
+	sta scr_row	; Set the row position to to the end of the line.
+	jsr findst	; Find the start of the line.
+	lda scr_row	; Get the start of the line.
+@update2:
+	sta f		; Set the starting line, to the start of the line.
+	jsr rdrw_ln	; Redraw the line.
+	lda scr_trow	; Get the real row position back.
+	sta scr_row	;
+	lda scr_tcol	; Get the real column position back.
+	sta scr_col	;
+	jsr update_pos	; Update the cursor's position.
+	dec d		;
+	bra @save1	;
+@shift:
+	ldy.w scr_ptr3	;
+	inc scr_ptr3	;
+	tyx		;
+	dey		;
+	ldb #1		;
+	stb d		;
+	jsr shftln	;
+	ldb #1		;
+	stb d		;
+	lda a		;
+	sta (ptr3), y	; store typed character into the input buffer.
+	lda scr_row	;
+	sta scr_trow	;
+	bra @update	;
+@save:
+	ldb d		;
+	bne @update	;
+@save1:
+	lda a		;
+	sta (ptr3), y	; store typed character into the input buffer.
+@incr:
+	inc scr_col	; Increment the cursor's x coordinate.
+	iny		;
+@wrapped:
+	ldb #1		;
+	stb f		;
+	ldb scr_col	;
+	cpb #maxcol+1	;
+	bcs @scrolled	;
+@print:
+	sta scr		; Echo typed character.
+	ldb f		;
+	beq @wrap	;
+	bra printc_end	;
+@scrolled:
+	ldb scr_row	;
+	cpb #maxrow	;
+	bcs @scroll	;
+@wrapped2:
+	ldb #0		;
+	stb f		;
+	bra @print	;
+@scroll:
+	sta scr		; Echo typed character.
+	clc		;
+	lda #1		;
+	sta wrapped	;
+	jsr scrl_down	;
+@wrap:
+	ldb #0
+	stb scr_col	;
+	ldb scr_row	;
+	cpb #maxrow	;
+	bcs @wrap2	;
+@wrap1:
+	inc scr_row	;
+@wrap2:
+	phx.w		;
+	clc		;
+	lda scr_row	;
+	adc scr_str	;
+	tax		;
+	jsr setbit	;
+	plx.w		;
+	jsr update_pos	;
+printc_end:
+	rts		;
+
+nl:
+	lda #0		; Reset A.
+	ldb (ptr3), y	; Is this character not a null terminator?
+	bne @scroll	; Yes, so don't overwrite it.
+	sta (ptr3), y	; No, so overwrite it.
+@scroll:
+	sta scr_col	; Move the cursor to the start of the next line.
+	lda scr_row	; Get the row position.
+	cmp #maxrow	; Are we at the bottom of the screen?
+	bcc @incr	; No, so move down one line.
+	jsr scrl_down	; Yes, so scroll down one line.
+	bra @end	; We are done.
+@incr:
+	inc scr_row	; Move the cursor down by one line.
+	jsr update_pos	; Update the cursor's position.
+@end:
+	lda #'\n'	; Print the newline.
+	sta a		;
+	rts		;
+
+
+clr_scr:
+	lda #maxrow	;
+	sta scr_end	;
+	lda #0		;
+	sta scr_str	;
+	sta.q bitabl	;
+	sta.q bitabl+8	;
+	tay		;
+	lda.w #$1FFF	; Set the clear count to $1FFF.
+	pha.w		; Push the clear count onto the stack.
+;	sta.w scr_ptr	;
+	lda.d #buffer	; Set the array to be cleared to the screen buffer.
+	pha.q		; Push the pointer onto the stack.
+	jsr clr_arr	; Clear the screen buffer.
+	tay		;
+	pla.q		; Pull the pointer off of the stack.
+	pla.w		; Pull the clear count off of the stack.
+	lda.w #$3FF	; Set the clear count to $3FF.
+	pha.w		; Push the clear count onto the stack.
+;	sta.w scr_ptr	;
+	lda.d #cmd_buf	; Set the array to be cleared to the command buffer.
+	pha.q		;
+	jsr clr_arr	; Clear the screen buffer.
+	pla.q		; Pull the pointer off of the stack.
+	pla.w		; Pull the clear count off of the stack.
+	and #0		; Reset A.
+	sta scr_col	;
+	sta scr_row	;
+	jsr update_pos	;
+	lda #$C		;
+	sta scr		;
+	rts		;
+
+en_step:
+	lda step	;
+	beq step_en	;
+	rts		;
+step_en:
+	lda #1		;
+	sta step	;
+	rts		;
+
+dis_step:
+	lda step	;
+	bne step_dis	;
+	rts		;
+step_dis:
+	lda #0		;
+	sta step	;
+	rts		;
+
+
+bs:
+	lda scr_col	; Are we at the far left of the screen?
+	beq @wrap	; Yes, so check for a wrapped line.
+	bra back	; No, so add the backspace to the buffer.
+@wrap:
+	jsr getbit	; Is this line, a wrapped line?
+	bcs @wrap1	; Yes, so check if the cursor is at the top.
+	rts		; No, so we're done.
+@wrap1:
+	lda scr_row	; Are we at the top of the screen?
+	beq @wrap2	; Yes, so check if the screen is at the top of the buffer.
+	bra @wrap3	; No, so start clearing the wrap bit.
+@wrap2:
+	lda scr_str	; Are we at the top of the buffer?
+	bne @scroll	; Yes, so scroll up.
+	rts		; No, so we're done.
+@scroll:
+	clc		; Clear the carry flag, so that we don't get odd behaviour.
+	jsr scrl_up	; Scroll up.
+	inc scr_row	; Move down by one row.
+@wrap3:
+	clc		; Clear the carry flag.
+	lda scr_row	; Add the cursor's row position,
+	adc scr_str	; and the screen's starting row.
+	tax		; Transfer that into X.
+@wrap4:
+	dec scr_row	; Move up by one row.
+	ldb #maxcol+1	; Move the cursor to the absolute right of the screen.
+	stb scr_col	;
+	jsr update_pos	; Update the cursor's position.
+back:
+	ldb #0		; Reset B, and some flags.
+	stb e		;
+	stb f		;
+	lda scr_row	; Save the current row position for later.
+	sta scr_trow	;
+	jsr findend	; Find the end of the line.
+	sta scr_row	; Set our row position to the end of the line.
+@find_st:
+	jsr findst	; Does this line take up more than one real line?
+	beq @shift	; No, so skip updating any other lines.
+	bcs @update	; Yes, so update the other lines.
+	lda scr_trow	; Get the real row position back.
+	sta scr_row	;
+@shift:
+	dey		; Decrement the buffer's offset.
+	lda #0		; Place a null terminator
+	sta (ptr3), y	; into the buffer.
+	tyx		; Copy the current cursor index to X.
+	iny		; Increment cursor index.
+	ldb #0		; Set shifting direction to left.
+	stb d		;
+	jsr shftln	; Shift line back by one character.
+	lda #$7F	; Print a backspace to the screen.
+	sta scr		;
+	lda e		; Are we updating more than one line?
+	beq @load	; No, so skip to the next step.
+@find_end:
+	jsr findend	; Yes, so find the end of the line.
+	sta e		; Set the end parameter to it.
+	lda scr_col	; Save the current column position for now.
+	sta scr_tcol	;
+	jsr rdrw_ln	; Start redrawing the line.
+	lda scr_tcol	; Get the real column position back.
+	sta scr_col	;
+@load:
+	lda scr_trow	; Get the real row position back.
+	sta scr_row	;
+	dec scr_col	; Move the cursor back by one column,
+	jsr update_pos	; and update it's position.
+	rts		; We are done.
+@update:
+	lda scr_row	; Set the line to start redrawing, to the start of the line.
+	sta f		;
+	inc e		; Set the redraw flag to true.
+	bra @shift	; Start shifting the line back.
+
+
+shftln:
+	ldb d		; Is the flag not set?
+	beq @dec_loop	; Yes, so shift, and decrement.
+	ldb #0		; Clear the B register.
+	bra @inc_loop	; No, so shift, and increment.
+@neg:
+	ldy.w zero	; Set the source poition to 0.
+	stb (ptr3), y	; Clear the character that is in the source.
+	bra @end	; We are done.
+@inc_loop:
+	sty.w scr_ptr2	; Save the source position for later.
+	ldy.w scr_ptr	; Get the previous cursor index.
+	cpy.w scr_ptr2	; Is the source position, at, or below the cursor index?
+	beq @inc_loop1	; Yes, so keep looping.
+	bcs @end	; No, so we're done.
+@inc_loop1:
+	ldy.w scr_ptr2	; Get the source position.
+	lda (ptr3), y	; Get the character from the source position.
+	phy.w		; Save the source position for later.
+	txy		; Set our position to the destination.
+	sta (ptr3), y	; Place the character from the source position, to the destination position.
+	ply.w		; Set our position back to the source.
+	stb (ptr3), y	; Clear the character that is in the source.
+	bng @neg	; The source underflowed, so set it back to zero,
+	dey		; Decrement the source position.
+	dex		; Decrement the destination position.
+	bra @inc_loop	; Keep looping.
+@dec_loop:
+	stx.w scr_ptr2	; Save the destination position for later.
+	lda (ptr3), y	; Is the character at the source position, a null terminator?
+	beq @end3	; Yes, so we're done.
+	phy.w		; No, so save the source position for later.
+	txy		; Set our position to the destination.
+	sta (ptr3), y	; Place the character from the source position, to the destination position.
+	inx		; Increment the destination position.
+	ply.w		; Set our position back to the source.
+	stb (ptr3), y	; Clear the character that is in the source.
+	iny		; Increment the source position.
+	bra @dec_loop	; Keep looping.
+@wrap:
+	tax		; Use the ending line as a parameter for setbit.
+	jsr setbit	; Set the wrap bit of the ending line.
+	bra @end5	; We are done.
+@wrap1:
+	tax		; Use the ending line as a parameter for clrbit.
+	jsr clrbit	; Clear the wrap bit of the ending line.
+	bra @end5	; We are done.
+@end:
+	lda (ptr3), y	; Is this character a null terminator?
+	bne @end1	; No, so just find the end of the line.
+	lda #$20	; Yes, so convert it to a space for now.
+	sta (ptr3), y	;
+@end1:
+	jsr findend	; Find the ending line.
+	sta d		; Save ending line for later.
+	lda (ptr3), y	; Is this character a space?
+	cmp #$20	;
+	bne @end5	; No, so skip the conversion.
+	lda #0		; Yes, so convert it back to zero.
+	sta (ptr3), y	;
+@end2:
+	lda d		; Get the ending line.
+	cmp scr_row	; Is the ending line greater than the starting line?
+	beq @end5	; No, so we're done.
+	bcs @wrap	; Yes, so set the wrap bit.
+	bra @end5	; No, so we're done.
+@end3:
+	jsr findend	; Find the ending line.
+	cpb #0		; Is the remainder zero?
+	beq @end4	; Yes, so check if the ending line is greater than the starting line.
+	bra @end5	; No, so we're done.
+@end4:
+	cmp scr_row	; Is the ending line greater than the starting line?
+	beq @end5	; No, so we're done.
+	bcs @wrap1	; Yes, so clear the wrap bit.
+@end5:
+	rts		; End of shftln.
+
+esc:
+	lda status	; Get the next character.
+	lda kbd		;
+	cmp #$1B	; Is this character an escape character?
+	beq shftesc	; Yes, so check the other set of escape routines.
+	lda status	; No, so wait for the next character.
+	beq @end	; We have an error, so discard it, and go back to getting user input.
+	lda kbd		; Get the escape code.
+	sta c		; Store the escape code, until we need it.
+	lda #0		; Set the D pseudo register to zero.
+	sta d		;
+	jsr isup	; Check if the user pressed up.
+	lda d		; Did the user press up?
+	bne @end	; Yes, so we're done.
+	jsr isdown	; No, so check if the user pressed down.
+	lda d		; Did the user press down?
+	bne @end	; Yes, so we're done.
+	lda #0		; No, so check if the user pressed left.
+	jsr isleft	;
+	lda d		; Did the user press left?
+	bne @end	; Yes, so we're done.
+	jsr isright	; No, so check if the user pressed right.
+@end:
+	lda #0		; Clear the D pseudo register.
+	sta d		;
+	rts		; We are done.
+
+shftesc:
+	lda status	; Skip the '['.
+	lda kbd		;
+	lda status	; Wait for the next character.
+	beq @end	; We have an error, so discard it, and go back to getting user input.
+	lda kbd		; Get the escape code.
+	sta c		; Store the escape code, until we need it.
+	lda #0		; Use the D pseudo register as a skip flag.
+	sta d		;
+	jsr isshftup	; Check if the user pressed shift+up.
+	lda d		; Was it successful?
+	bne @end	; Yes, so we're done.
+	jsr isshftdown	; No, so check if the user pressed shift+down.
+@end:
+	lda #0		; Clear the D pseudo register.
+	sta d		;
+	rts		; We are done.
+
+
+isup:
+	lda c		; Load the escape code into the accumulator.
+	cmp #'A'	; Did the user press the up arrow key?
+	bne @end	; No, so we're done.
+	lda scr_row	; Yes, but is the cursor at the top of the screen?
+	beq @scroll	; Yes, so check if we need to scroll.
+@check2:
+	lda c		; No, so load the escape code back into the accumulator.
+	cmp #'A'	; Did the user press the up arrow key?
+	beq @up		; Yes, so move the cursor up.
+	bra @end	; No, so we're done.
+@up:
+	dec scr_row	; Move the cursor up a line.
+	jsr update_pos	; Update it's position.
+	lda #1		; Tell the escape routine that we succeded.
+	sta d		;
+	rts		; We are done.
+@scroll:
+	lda scr_str	; Are we at the top of the screen buffer?
+	beq @end	; Yes, so we're done.
+	jsr scrl_up	; No, so scroll up.
+	lda #1		; Tell the escape routine that we were successful.
+	sta d		;
+@end:
+	rts		; End of isup.
+
+
+isdown:
+	lda c		; Load the escape code into the accumulator.
+	cmp #'B'	; Did the user press the down arrow key?
+	bne @end	; No, so we're done.
+	lda scr_row	; Yes, so start checking the y coordinate of the cursor.
+	cmp #maxrow	; Is the cursor at the bottom of the screen?
+	beq @scroll	; Yes, so scroll down.
+	lda c		; No, so load the escape code back into the accumulator.
+	cmp #'B'	; Did the user press the down arrow key?
+	beq @down	; Yes, so move the cursor down.
+	bra @end	; No, so we're done.
+@down:
+	inc scr_row	; Move the cursor down a line.
+	jsr update_pos	; Update it's position.
+	lda #1		; Tell the escape routine that we succeded.
+	sta d		;
+	rts		; We are done.
+@scroll:
+	lda scr_row	; Save the cursor's row number.
+	sta scr_trow	;
+	lda scr_col	; Save the cursor's column number.
+	sta scr_tcol	;
+	jsr scrl_down	; Scroll down.
+	lda scr_trow	; Load the cursor's row number.
+	sta scr_row	;
+	lda scr_tcol	; Load the cursor's column number.
+	sta scr_col	;
+	lda #1		; Tell the escape routine that we were successful.
+	sta d		;
+@end:
+	rts		; End of isdown.
+
+
+isright:
+	lda c		; Load the escape code into the accumulator.
+	cmp #'C'	; Did the user press the right arrow key?
+	bne @end2	; No, so we're done.
+	lda scr_col	; Yes, so start checking the x coordinate of the cursor.
+	cmp #maxcol	; Is the cursor at the far right of the screen?
+	beq @wrap	; Yes, so check if this is a wrapped line.
+	bra @right	; No, so move the cursor right, like normal.
+@wrap:
+	inc scr_row	; Move down a row.
+	jsr getbit	; Is the current line, a wrapped line?
+	bcs @incr	; Yes, so leave the cursor where it is.
+	dec scr_row	; No, so move the cursor back up a row.
+	bra @end2	; We are done.
+@scroll:
+	lda scr_str	; Are we at the top of the screen buffer?
+	beq @end	; Yes, so we're done.
+	lda #1		; No, so scroll down.
+	sta wrapped	; Set the wrapped flag.
+	jsr scrl_down	; Scroll down.
+	bra @end	; We are done.
+@incr:
+	lda #0		; Set the cursor to the far left of the screen.
+	sta scr_col	;
+	lda scr_row	; Get the current row number.
+	cmp #maxrow	; Are we at the bottom of the screen?
+	beq @end1	; No, so we're done.
+	bcs @scroll	; Yes, so check if we are scrolling down.
+	bra @end1	; No, so we're done.
+@right:
+	inc scr_col	; Move the cursor right by one character.
+	jsr update_pos	; Update it's position.
+	rts		; End of isright.
+@end:
+	dec scr_row	; Move back up a row.
+@end1:
+	jsr update_pos	; Update the cursor position.
+@end2:
+	lda #0		; Unset the wrapped flag.
+	sta wrapped	;
+	rts		; End of isright.
+
+
+isleft:
+	lda c		; Load the escape code into the accumulator.
+	cmp #'C'	; Did the user press right?
+	beq @end1	; Yes, so we're done
+	lda scr_col	; No, but is the cursor at the far left of the screen?
+	beq @wrap	; Yes, so start checking if this is a wrapped line.
+	lda c		; No, so load the escape code back into the accumulator.
+	cmp #'D'	; Did the user press the left arrow key?
+	beq @left	; Yes, so move the cursor left.
+	bra @end1	; No, so we're done.
+@wrap:
+	jsr getbit	; Is the current line, a wrapped line?
+	bcs @decr	; Yes, so wrap back up a line.
+	bra @end1	; No, so we're done.
+@decr:
+	lda scr_row	; Is the cursor at the top of the screen?
+	beq @decr1	; Yes, so don't move up a line.
+	lda #1		; No, so set the wrapped flag.
+	sta wrapped	;
+	dec scr_row	; Move the cursor up one line.
+@decr1:
+	lda #maxcol	; Move the Cursor to the far right of the screen.
+	sta scr_col	;
+	lda #1		; Tell the escape routine that we were successful.
+	sta d		;
+	lda scr_row	; Are we at the top of the screen?
+	beq @scroll	; Yes, so check if we need to scroll.
+	bra @end	; No, so we're done.
+@scroll:
+	lda wrapped	; Was the wrapped flag set somewhere else?
+	bne @end	; Yes so we're done.
+	lda scr_str	; No, but are we actually at the top of the screen buffer?
+	beq @end1	; Yes, so we're done.
+	jsr scrl_up	; No, so scroll up.
+	bra @end1	; We are done.
+@left:
+	dec scr_col	; Move the cursor left a character.
+	jsr update_pos	; Update it's position.
+	lda #1		; Tell the escape routine that we succeded.
+	sta d		;
+	rts		; We are done
+@end:
+	jsr update_pos	; Update the cursor position.
+@end1:
+	lda #0		; Unset the wrapped flag.
+	sta wrapped	;
+	rts		; End of isleft.
+
+
+isshftup:
+	lda c		; Load the escape code back into the accumulator.
+	cmp #'A'	; Did the user press the up arrow key?
+	bne @end	;
+	lda #1		;
+	sta d		;
+	lda scr_str	;
+	beq @end	;
+@shftup:
+	jsr scrl_up	;
+	lda #1		;
+	sta d		;
+@end:
+	rts		;
+
+
+isshftdown:
+	lda c		; Load the escape code back into the accumulator.
+	cmp #'B'	; Did the user press the down arrow key?
+	bne @end	;
+	lda #1		;
+	sta d		;
+	lda scr_end	;
+	cmp #71		;
+	bcs @end	;
+@shftdown:
+	jsr scrl_down	;
+	lda #1		;
+	sta d		;
+@end:
+	rts		;
+
+
+update_pos:
+	ldb #1		; Set the F pseudo register to one, to fix some bugs.
+	stb f		;
+	clc		; Clear the carry flag.
+	lda scr_row	; Add the cursor's line number,
+	adc scr_str	; with the starting line number to get the absolute line number.
+	tay		; Place it in the Y regster for now.
+	mul #maxcol+1	; Multiply the line number by the screen's max column count, plus 1.
+	clc		; Clear the carry flag.
+	adc scr_col	; Add the cursor's column number to get the screen index.
+	tay		; Place the index into the Y register.
+	tba		; Reset A.
+	lda #$1B	; Print an escape character
+	sta scr		; to the screen.
+	lda #'['	; Print '['
+	sta scr		; to the screen, and start the escape sequence.
+	jsr getrow	; Start printing the row number to the screen.
+	jsr getcol	; Start printing the column number to the screen.
+	lda #'H'	; Print 'H'
+	sta scr		; to the screen.
+	rts		; End of update_pos.
+
+getrow:
+	lda scr_row	; Get the cursor's y coordinate.
+	bra bcd		; Convert it to BCD.
+getcol:
+	lda #';'	; Print ';'
+	sta scr		; to the screen.
+	lda scr_col	; Get the cursor's x coordinate.
+bcd:
+	div #10		; Divide A by 10.
+	ora #'0'	; Convert it to ascii, and
+	sta scr		; print to the screen.
+	tba		; Get the remainder.
+	ora #'0'	; Convert it to ascii, and
+	sta scr		; print to the screen.
+	rts		; End of bcd.
+
+scrl_down:
+	inc scr_str	; Increment the starting line of the screen.
+	inc scr_end	; Increment the ending line of the screen.
+	lda #$1B	; Print an escape character
+	sta scr		; to the screen.
+	lda #'['	; Print '['
+	sta scr		; to the screen, and start the escape sequence.
+	lda #'T'	; Print 'T'
+	sta scr		; to the screen, and end the escape sequence.
+	lda scr_row	; Get the cursor's line number.
+	pha 		; Save it in the stack.
+	lda wrapped	; Was the wrapped flag set?
+	beq @save	; Yes, so save the cursor position.
+@redraw:
+	jsr rdrw_row	; No, so redraw this row.
+	lda wrapped	; Was the wrapped flag set?
+	beq @load	; Yes, so load the previous cursor position back.
+	bra @end	; No, so we're done.
+@save:
+	lda scr_col	; Get the cursor's column number.
+	pha 		; Save it in the stack.
+	bra @redraw	; Start redrawing the current row.
+@load:
+	pla 		; Get the cursor's previous column number back.
+	sta scr_col	;
+@end:
+	pla 		; Get the cursor's previous line number back.
+	sta scr_row	;
+	jsr update_pos	; Update the cursor's position.
+	lda #0		; Clear the wrapped flag.
+	sta wrapped	;
+@end1:
+	rts		; End of scrl_down.
+
+scrl_up:
+	dec scr_str	;
+	dec scr_end	;
+	lda #$1B	; Print an escape character
+	sta scr		; to the screen.
+	lda #'['	; Print '['
+	sta scr		; to the screen, and start the escape sequence.
+	lda #'S'	; Print 'S'
+	sta scr		; to the screen, and end the escape sequence.
+	lda scr_row	;
+	pha 		;
+	lda scr_col	;
+	pha 		;
+	lda #0		;
+	sta scr_row	;
+	jsr rdrw_row	;
+	pla 		;
+	sta scr_col	;
+	pla 		;
+	sta scr_row	;
+	jsr update_pos	;
+@end:
+	rts		;
+
+rdrw_row:
+	lda #0		;
+	sta scr_col	;
+	jsr update_pos	;
+@loop:
+	lda (ptr3), y	;
+	beq @incr	;
+	sta scr		;
+@incr:
+	inc scr_col	;
+	lda (ptr3), y	;
+	beq @skip	;
+@incr1:
+	iny		;
+@incr2:
+	lda scr_col	;
+	cmp #maxcol+1	;
+	bcs @end	;
+	bra @loop	;
+@skip:
+	lda #' '	;
+	sta scr		; to the screen.
+	bra @incr1	;
+@end:
+	lda #0		;
+	sta scr_col	;
+	jsr update_pos	;
+@end1:
+	rts		;
+
+rdrw_ln:
+	lda scr_row	;
+	pha 		;
+	lda f		;
+	sta scr_row	;
+	lda scr_col	;
+	pha 		;
+	jsr update_pos	;
+@loop:
+	lda scr_row	;
+	cmp e		;
+	beq @loop1	;
+	bcs @end	;
+@loop1:
+	jsr rdrw_row	;
+@incr:
+	inc scr_row	;
+	bra @loop	;
+@end:
+	pla 		;
+	sta scr_col	;
+	pla 		;
+	sta scr_row	;
+	jsr update_pos	;
+	lda #0		;
+	sta e		;
+	sta f		;
+	rts		;
+
+set_ptr:
+	cpb #1		; Are we setting the second pointer?
+	beq @ptr2	; Yes, so start setting it.
+	cpb #2		; No, but are we setting the third pointer?
+	beq @ptr3	; Yes, so start setting it.
+@ptr1:
+	stb.q ptr	; Reset the first pointer.
+	sta.q ptr	; No, so set the first pointer.
+	bra @end	; We are done.
+@ptr2:
+	stb.q ptr2	; Reset the second pointer.
+	sta.q ptr2	; Set the second pointer.
+	bra @end	; We are done.
+@ptr3:
+	stb.q ptr3	; Reset the third pointer.
+	sta.q ptr3	; Set the third pointer.
+@end:
+	rts		; End of set_ptr.