- Implemented the multiply expression into the assembler.

- Implemented support for the SIB addressing mode into
  the assembler.

  SIB is short for "Scale Index, and Base", and works
  much like x86's version of SIB (scale*index+base),
  although my version supports any scale value between
  1, and 256.

- Redid the line shifting routine in SuBEditor.

  It now uses memcpy, and memset to do that, and also
  supports shifting the line left, or right by any
  number of characters.

1 files changed, 351 insertions, 78 deletions

diff --git a/programs/sub-suite/subeditor.s b/programs/sub-suite/subeditor.s
index f6b647f..83fe179 100644
--- a/programs/sub-suite/subeditor.s
+++ b/programs/sub-suite/subeditor.s
@@ -196,11 +196,22 @@ clrbit:
 
 setbit:
 	pha.q			; Preserve A.
+	phb.q			; Preserve B.
+	mov b, s		; Save the bit.
 	des			; Create the stack frame.
 	lea s, (sp+1)		; Get the address of the bitmask.
 	jsr bitpos		; Get the bit, and byte position.
 	ins			; Cleanup the stack frame.
+	cpb #1			; Is the bit set?
+	bne @clear		; No, so clear the bit.
+@set:
 	or  (bitabl)+a, (s)	; Set the bit of the current row number to one.
+	bra @end		; We are done.
+@clear:
+	not (s)			; Invert the bitmask.
+	and (bitabl)+a, (s)	; Set the bit of the current row number to zero.
+@end:
+	plb.q			; Restore B.
 	pla.q			; Restore A.
 	rts			; End of setbit.
 
@@ -257,21 +268,19 @@ cmd_cpy:
 	sta scr_trow	; Save it for later.
 	lea d, (buffer)	; Get the screen buffer.
 	mov s, y	; Get the cursor index.
+	lea f, 1	; Set the decrement offset to the left flag.
 	jsr find_end	; Find the end of the line.
 	div #maxcol+1	; Get the ending 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.
+	sub scr_str	; Offset the row position, back by the screen's starting point.
 @start:
 	sta scr_row	; Set the row position to the end of the line.
 	sta rege	; 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.
+	add 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.
@@ -338,13 +347,52 @@ findst:
 	rts		; End of findst.
 
 
+;find_end:
+;	mov a, s	; Set the loop counter.
+;@loop:
+;	inc		; Increment the loop counter.
+;	cmp (d+a-1), #0	; Did we hit the null terminator?
+;	bne @loop	; No, so keep looping.
+;@end:
+;	rts		; End of find_end2.
+
+
 find_end:
+	phb.q		; Preserve B.
+	phx.q		; Preserve X.
+	phy.q		; Preserve Y.
+	phe.q		; Preserve E.
 	mov a, s	; Set the loop counter.
+	div #maxcol+1	; Get the row position.
+	tay		; Save the row position.
+	mov b, d	; Preserve the string pointer.
+	mov x, s	; Preserve the cursor position.
+	mov d, a	;
+	xor s, s	; Reset S.
 @loop:
+	inc d		; Increment the line.
+	mov e, d	; Save the line.
+	jsr getbit	; Get the linewrap bit.
+	mov d, e	; Get the line.
+	cmp #1		; Is this the end of the line?
+	beq @loop	; No, so keep looping.
+@loop2_1:
+	mov a, d	; Get the ending row position.
+	sub a, f	; Decrement the row position by the offset.
+	mul #maxcol+1	; Get the loop counter.
+	cmp a, x	; Is the new loop counter less than the old loop counter?
+	mcc a, x	; Set the loop counter to the old loop counter if so.
+	mov d, b	; Restore the string pointer.
+	mov s, x	; Restore the cursor position.
+@loop2:
 	inc		; Increment the loop counter.
 	cmp (d+a-1), #0	; Did we hit the null terminator?
-	bne @loop	; No, so keep looping.
+	bne @loop2	; No, so keep looping.
 @end:
+	ple.q		; Restore E.
+	ply.q		; Restore Y.
+	plx.q		; Restore X.
+	plb.q		; Restore B.
 	rts		; End of find_end.
 
 
@@ -353,6 +401,11 @@ get_endrow:
 	div #maxcol+1	; Get the ending row.
 	rts		; End of get_endrow
 
+;get_endrow2:
+;	jsr find_end2	; Find the end of the line.
+;	div #maxcol+1	; Get the ending row.
+;	rts		; End of get_endrow
+
 
 print_char:
 	phb.q		; Preserve B.
@@ -392,6 +445,7 @@ printc:
 @update1:
 	lea d, (buffer)	; Get the screen buffer.
 	mov s, y	; Get the cursor index.
+	lea f, 1	; Set the decrement offset to one.
 	jsr get_endrow	; Get the ending line.
 	mov d, a	;
 	mov s, scr_trow	; Get the current row position.
@@ -414,7 +468,8 @@ printc:
 ;	stb regd	;
 	lea d, (buffer)	; Get the screen buffer.
 	mov.w s, scr_ptr; Get the cursor index.
-	mov f, #1	; Set the left flag to true.
+	lea f, 1	; Set the shift length to one.
+	lea c, 1	; Set the left flag to true.
 	jsr shftln	;
 	ldb #1		;
 	stb regd	;
@@ -454,7 +509,7 @@ printc:
 	bra @print	;
 @scroll:
 	sta scr		; Echo typed character.
-	clc		;
+;	clc		;
 	lda #1		;
 	sta wrapped	;
 	jsr scrl_down	;
@@ -474,6 +529,7 @@ printc:
 ;	tax		;
 	mov d, scr_row	; Get the row position.
 	add d, scr_str	; Add the row offset to the row position.
+	lea s, 1	; Set the bit to one.
 	jsr setbit	; Set the bit of that row.
 ;	plx.w		;
 	jsr update_pos	;
@@ -560,13 +616,11 @@ bs:
 	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.
+	add scr_str	; and the screen's starting row.
 	tax		; Transfer that into X.
 @wrap4:
 	dec scr_row	; Move up by one row.
@@ -581,6 +635,7 @@ back:
 	sta scr_trow	;
 	lea d, (buffer)	; Get the screen buffer.
 	mov s, y	; Get the cursor index.
+	lea f, 0	; Set the decrement offset to zero.
 	jsr get_endrow	; Get the ending line.
 	sta scr_row	; Set our row position to the end of the line.
 @find_st:
@@ -599,7 +654,8 @@ back:
 	stb regd	;
 	lea d, (buffer)	; Get the screen buffer.
 	mov s, y	; Get the cursor index.
-	mov f, #0	; Set the left flag to false.
+	lea f, 1	; Set the shift length to one.
+	lea c, 0	; Set the left flag to false.
 	jsr shftln	; Shift line back by one character.
 	lda #$7F	; Print a backspace to the screen.
 	sta scr		;
@@ -608,6 +664,7 @@ back:
 @find_end:
 	lea d, (buffer)	; Get the screen buffer.
 	mov s, y	; Get the cursor index.
+	lea f, 1	; Set the decrement offset to one.
 	jsr get_endrow	; Yes, so Get the ending line.
 	mov d, a	;
 	mov s, scr_trow	; Get the current row position.
@@ -630,66 +687,288 @@ back:
 	bra @shift	; Start shifting the line back.
 
 
+;shftln:
+;	pha.q			; Preserve A.
+;	phb.q			; Preserve B.
+;	and f, f		; Is the left flag not set?
+;	beq @right		; Yes, so shift the line to the right.
+;;	txa			; Get the end of the line.
+;	jsr find_end		; Find the end of the line.
+;	dec			; Decrement the source position.
+;	bra @left		; No, so shift the line to the left.
+;@minus:
+;	and #0			; Set the source poition to 0.
+;	mov (d), a		; Clear the character that is in the source.
+;	bra @lend		; We are done.
+;@left:
+;	cmp s, a		; Is the cursor index, at, or below the source position?
+;	beq @left1		; Yes, so keep looping.
+;	bcs @lend		; No, so we're done.
+;@left1:
+;	cmp #0			; Is the source position less than 0?
+;	bcc @minus		; Yes, so set the source position to zero.
+;	mov (d+a+1), (d+a)	; No, so shift the current character to the left by one.
+;	mov (d+a), #0		; Clear the current character.
+;	dec			; Decrement the source position.
+;	bra @left		; Keep looping.
+;@right:
+;	cmp (d+s), #0		; Is this character a null terminator?
+;	beq @rend		; Yes, so we're done.
+;	mov (d+s-1), (d+s)	; No, so shift the current character to the right by one.
+;	mov (d+s), #0		; Clear the current character.
+;	inc s			; Increment the source position.
+;	bra @right		; Keep looping.
+;@wrap:
+;	mov d, a		; Get the ending line.
+;	lea s, f		; Set the bit to the left flag.
+;	jsr setbit		; Set the wrap bit of the ending line.
+;	bra @end		; We are done.
+;@lend:
+;	lea s, (a+2)		; Add 2 to the source position.
+;	jsr find_end		; Find the end of the line.
+;	dec			; Decrement the end of line position.
+;	div #maxcol+1		; Get the ending line.
+;@lend2:
+;	cmp scr_row		; Is the ending line greater than the starting line?
+;	beq @end		; No, so we're done.
+;	bcs @wrap		; Yes, so set the wrap bit.
+;	bra @end		; No, so we're done.
+;@rend:
+;	lea f, 0		; Set the decrement offset to one.
+;	jsr find_end		; Find the end of the line.
+;	dec			; Decrement the end of line position.
+;	div #maxcol+1		; Get the ending line.
+;	cpb #0			; Is the remainder zero?
+;	bne @end		; No, so we're done.
+;@rend2:
+;	cmp scr_row		; Is the ending line greater than the starting line?
+;	beq @end		; No, so we're done.
+;	bcs @wrap		; Yes, so clear the wrap bit.
+;@end:
+;	plb.q			; Restore B.
+;	pla.q			; Restore A.
+;	rts			; End of shftln.
+
+
+;minmax:
+;	psh.q d			; Preserve D.
+;	psh.q s			; Preserve S.
+;	mov d, e		; Get the shift length.
+;	mov s, b		; Get the ending position.
+;	jsr max			; Get the largest value.
+;	mov f, a		; Save the largest value.
+;	jsr min			; Get the smallest value.
+;	pul.q s			; Restore S.
+;	pul.q d			; Restore D.
+;	rts			; End of minmax.
+
+
+;shftln:
+;	pha.q			; Preserve A.
+;	phb.q			; Preserve B.
+;	phx.q			; Preserve X.
+;	phy.q			; Preserve Y.
+;	phe.q			; Preserve E.
+;	mov x, d		; Get the string pointer.
+;	mov y, s		; Get the cursor position.
+;	mov e, f		; Get the shift length.
+;@find_end:
+;	lea f, 1		; Set the decrement offset to the left flag.
+;	jsr find_end		; Find the end of the line.
+;	mov f, e		; Get the shift length.
+;	tab			; Save the end position for later.
+;	and #0			; Reset A.
+;	dec			; Set our offset to -1.
+;	and c, c		; Is the left flag set?
+;	mne a, f		; Set our offset to the length argument if so.
+;@copy:
+;	add a, s		; Add the cursor position with the offset.
+;	lea s, (d+s)		; Get the address of the string pointer, at the cursor position.
+;	lea d, (d+a)		; Get the address of the string pointer, at the cursor position, plus the offset.
+;	jsr minmax		; Get the minimum, and maximum values.
+;@check_length:
+;	cpe #2			; Is the shift length greater than one?
+;	bcc @offset0		; No, so skip the subtraction below.
+;	cmp f, y		; Yes, and is the end position greater than, or equal to the the cursor position?
+;	bcc @offset		; No, so skip the subtraction below.
+;	and c, c		; Yes, and is the left flag set?
+;	beq @offset0		; No, so skip the subtraction below.
+;@sub:
+;	tya			; Set the offset to the cursor position.
+;	bra @offset		; Subtract the offset.
+;@offset0:
+;	sub f, a		; Subtract the end position by the shift length.
+;	bra @sub		; Subtract the cursor position.
+;@offset:
+;	sub f, a		; Subtract the offset.
+;@copy2:
+;	jsr memcpy		; Copy the string from the cursor, to the cursor plus the offset.
+;@clear:
+;	jsr minmax		; Get the minimum, and maximum values.
+;	cmp #1			; Is the smallest value equal to one?
+;	bne @clear2		; No, so skip incrementing the value.
+;	inc			; Increment the smallest value.
+;@clear2:
+;	sub f, a		; Subtract the end position by the shift length.
+;	mov d, y		; Get the cursor position.
+;	and c, c		; Is the left flag set?
+;	meq d, f		; Get the end position, minus the shift length if so.
+;	lea d, (x+d)		; Get the address of the string pointer, at the offset.
+;	xor s, s		; Reset S.
+;	mov f, e		; Restore the shift length.
+;	jsr memset		; Clear shift length bytes of the string, from the offset.
+;@neg:
+;	and c, c		; Is the left flag set?
+;	bne @get_rows		; Yes, so don't negate the shift length.
+;	neg f			; Negate the shift length.
+;@get_rows:
+;	mov x, b		; Save the end position.
+;	lea a, (b+f)		; Add, or subtract the end position, by the shift length.
+;	div #maxcol+1		; Get the new ending line.
+;	mov e, a		; Save the ending line.
+;	xor f, f		; Reset F.
+;	and c, c		; Is the left flag set?
+;	meq f, b		; Save the remainder of the ending line if not.
+;	tya			; Get the cursor position.
+;	div #maxcol+1		; Get the cursor line.
+;	and c, c		; Is the left flag set?
+;	meq a, e		; Set the starting line to the new ending line if not.
+;	tay			; Save the starting line.
+;	txa			; Get the end position.
+;	div #maxcol+1		; Get the old ending line.
+;	and c, c		; Is the left flag set?
+;	mne a, e		; Set the ending line to the new ending line if so.
+;	tab			; Save the ending line.
+;	and c, c		; Is the left flag set?
+;	bne @inc		; Yes, so increment the starting line.
+;	cmp y, b		; No, but is the starting line less than the ending line?
+;	bcs @loop		; No, so don't increment.
+;	iny			; Yes, so increment the starting line.
+;	bra @getbit		; Get the bit.
+;@loop:
+;	xor s, s		; Reset S.
+;	cmp y, b		; Is the current line greater than the ending line?
+;	beq @rem		; The current line is equal to the ending line, so check the remainder.
+;	bcs @end		; Yes, so we're done.
+;	bra @getbit		; No, so get the bit.
+;@rem:
+;	and f, f		; Is the remainder zero?
+;	bne @end		; No, so we're done.
+;@getbit:
+;	mov d, y		; Get the current line.
+;	jsr getbit		; Get the linewrap bit of that line.
+;	cmp a, c		; Is the linewrap bit the opposite value of the left flag?
+;	beq @inc		; No, so keep looping.
+;@setbit:
+;	mov d, y		; Get the current line.
+;	mov s, c		; Get the left flag.
+;	jsr setbit		; Set the linewrap bit to the left flag.
+;@inc:
+;	iny			; Increment the current line.
+;	bra @loop		; Keep looping.
+;@end:
+;	ple.q			; Restore E.
+;	ply.q			; Restore Y.
+;	plx.q			; Restore X.
+;	plb.q			; Restore B.
+;	pla.q			; Restore A.
+;	rts			; End of shftln.
+
+
 shftln:
 	pha.q			; Preserve A.
 	phb.q			; Preserve B.
-	and f, f		; Is the left flag not set?
-	beq @right		; Yes, so shift the line to the right.
-;	txa			; Get the end of the line.
-	jsr find_end		; Find the end of the line.
-	dec			; Decrement the source position.
-	bra @left		; No, so shift the line to the left.
-@minus:
-	and #0			; Set the source poition to 0.
-	mov (d), a		; Clear the character that is in the source.
-	bra @lend		; We are done.
-@left:
-	cmp s, a		; Is the cursor index, at, or below the source position?
-	beq @left1		; Yes, so keep looping.
-	bcs @lend		; No, so we're done.
-@left1:
-	cmp #0			; Is the source position less than 0?
-	bcc @minus		; Yes, so set the source position to zero.
-	mov (d+a+1), (d+a)	; No, so shift the current character to the left by one.
-	mov (d+a), #0		; Clear the current character.
-	dec			; Decrement the source position.
-	bra @left		; Keep looping.
-@right:
-	cmp (d+s), #0		; Is this character a null terminator?
-	beq @rend		; Yes, so we're done.
-	mov (d+s-1), (d+s)	; No, so shift the current character to the right by one.
-	mov (d+s), #0		; Clear the current character.
-	inc s			; Increment the source position.
-	bra @right		; Keep looping.
-@wrap:
-	mov d, a		; Get the ending line.
-	jsr setbit		; Set the wrap bit of the ending line.
-	bra @end		; We are done.
-@wrap1:
-	mov d, a		; Get the ending line.
-	jsr clrbit		; Clear the wrap bit of the ending line.
-	bra @end		; We are done.
-@lend:
-	lea s, (a+2)		; Add 2 to the source position.
-	jsr find_end		; Find the end of the line.
-	dec			; Decrement the end of line position.
-	div #maxcol+1		; Get the ending line.
-@lend2:
-	cmp scr_row		; Is the ending line greater than the starting line?
-	beq @end		; No, so we're done.
-	bcs @wrap		; Yes, so set the wrap bit.
-	bra @end		; No, so we're done.
-@rend:
+	phx.q			; Preserve X.
+	phy.q			; Preserve Y.
+	phe.q			; Preserve E.
+	psh.q bp		; Preserve BP.
+	mov x, d		; Get the string pointer.
+	mov y, s		; Get the cursor position.
+	mov e, f		; Get the shift length.
+	and c, c		; Is the left flag set?
+	bne @find_end		; Yes, so find the end of the line.
+	cmp s, f		; No, but is the cursor position greater than, or equal to the shift length?
+	bcc @end		; No, so we're done.
+@find_end:
+	lea f, 1		; Set the decrement offset to the left flag.
 	jsr find_end		; Find the end of the line.
-	dec			; Decrement the end of line position.
-	div #maxcol+1		; Get the ending line.
-	cpb #0			; Is the remainder zero?
+	mov f, e		; Get the shift length.
+	sub a, c		; Decrement the old end position, if the left flag is set.
+	tab			; Save the old end position for later.
+	mov a, f		; Get the shift length.
+	neg a			; Negate the shift length.
+	and c, c		; Is the left flag set?
+	mne a, f		; Set our offset to the shift length if so.
+	lea bp, (b+a)		; Add the old end position, with the offset to get the new end position.
+@copy:
+	add a, y		; Add the cursor position with the offset.
+	lea s, (x+y)		; Get the address of the string pointer, at the cursor position.
+	lea d, (x+a)		; Get the address of the string pointer, at the cursor position, plus the offset.
+	mov f, b		; Get the old end position.
+	sub f, y		; Subtract the old end position, by the cursor position.
+	jsr memcpy		; Copy the string from the cursor, to the cursor plus the offset.
+@clear:
+	tya			; Get the cursor position.
+	and c, c		; Is the left flag set?
+	meq a, bp		; Set our offset to the new end position if not.
+	lea d, (x+a)		; Get the address of the string pointer, at the offset position.
+	xor s, s		; Reset S.
+	mov f, e		; Get the shift length.
+	jsr memset		; Clear shift length bytes of the string, from the offset.
+@get_rows:
+	mov x, b		; Save the old end position.
+	mov a, bp		; Get the new end position.
+	div #maxcol+1		; Get the new ending line.
+	mov e, a		; Save the ending line.
+	xor f, f		; Reset F.
+	and c, c		; Is the left flag set?
+	meq f, b		; Save the remainder of the ending line if not.
+	tya			; Get the cursor position.
+	div #maxcol+1		; Get the cursor line.
+	mov bp, a		; Save the cursor line.
+	and c, c		; Is the left flag set?
+	meq a, e		; Set the starting line to the new ending line if not.
+	tay			; Save the starting line.
+	txa			; Get the old end position.
+	div #maxcol+1		; Get the old ending line.
+	cmp bp, a		; Is the cursor line greater than, or equal to the old ending line?
+	mcs a, bp		; Get the cursor line if so.
+	inc			; Increment the line.
+	and c, c		; Is the left flag set?
+	mne a, e		; Set the ending line to the new ending line if so.
+	tab			; Save the ending line.
+	and c, c		; Is the left flag set?
+	bne @inc		; Yes, so increment the starting line.
+	cmp y, b		; No, but is the starting line less than the ending line?
+	bcs @loop		; No, so don't increment.
+	iny			; Yes, so increment the starting line.
+	bra @getbit		; Get the bit.
+@loop:
+	xor s, s		; Reset S.
+	cmp y, b		; Is the current line greater than the ending line?
+	beq @rem		; The current line is equal to the ending line, so check the remainder.
+	bcs @end		; Yes, so we're done.
+	bra @getbit		; No, so get the bit.
+@rem:
+	and f, f		; Is the remainder zero?
 	bne @end		; No, so we're done.
-@rend2:
-	cmp scr_row		; Is the ending line greater than the starting line?
-	beq @end		; No, so we're done.
-	bcs @wrap1		; Yes, so clear the wrap bit.
+@getbit:
+	mov d, y		; Get the current line.
+	jsr getbit		; Get the linewrap bit of that line.
+	cmp a, c		; Is the linewrap bit the opposite value of the left flag?
+	beq @inc		; No, so keep looping.
+@setbit:
+	mov d, y		; Get the current line.
+	mov s, c		; Get the left flag.
+	jsr setbit		; Set the linewrap bit to the left flag.
+@inc:
+	iny			; Increment the current line.
+	bra @loop		; Keep looping.
 @end:
+	pul.q bp		; Restore BP.
+	ple.q			; Restore E.
+	ply.q			; Restore Y.
+	plx.q			; Restore X.
 	plb.q			; Restore B.
 	pla.q			; Restore A.
 	rts			; End of shftln.
@@ -987,12 +1266,9 @@ 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.
+	mov scr, #'\e'	; Print an escape character to the screen.
+	mov scr, #'['	; Print '[' to the screen, and start the escape sequence.
+	mov scr, #'T'	; Print 'T' 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?
@@ -1022,12 +1298,9 @@ 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.
+	mov scr, #'\e'	; Print an escape character to the screen.
+	mov scr, #'['	; Print '[' to the screen, and start the escape sequence.
+	mov scr, #'S'	; Print 'S' to the screen, and end the escape sequence.
 	lda scr_row	;
 	pha 		;
 	lda scr_col	;