Made both the assembly language monitor, and the

emulator smaller, and faster.

I am also starting to make SuBEditor's source code
more readable.

1 files changed, 156 insertions, 134 deletions

diff --git a/programs/subeditor.s b/programs/subeditor.s
index 5e6ce08..fddc729 100644
--- a/programs/subeditor.s
+++ b/programs/subeditor.s
@@ -3,6 +3,16 @@
 ; Writen in Sux assembly by
 ; mr b0nk 500 <b0nk@b0nk.xyz>
 
+; I/O constants.
+status	= $C000		; Keyboard status.
+scr	= $C001		; Character that is to be printed.
+kbd	= $C002		; Character from the Keyboard.
+step	= $C010		; Enables clock stepping, when set.
+
+; Screen constants.
+maxrow	= 23		; Screen's row count.
+maxcol	= 79		; Screen's column count.
+
 .org $A000
 ; String Literals/Constants.
 tok:
@@ -72,27 +82,29 @@ bitabl:
 	.qword 0
 	.qword 0
 scr_str:
-	.byte $0
+	.byte 0
 scr_end:
-	.byte $0
+	.byte 0
 wrapped:
-	.byte $0
+	.byte 0
 
 ; Pointers
 ptr:
-	.qword $0
+	.qword 0
 ptr2:
-	.qword $0
+	.qword 0
 ptr3:
-	.qword $0
+	.qword 0
 ptr4:
-	.qword $0
+	.qword 0
 ptr5:
-	.qword $0
+	.qword 0
 ptr6:
-	.qword $0
+	.qword 0
 scr_ptr3:
-	.word $0
+	.word 0
+g:
+	.byte 0
 
 ; Main program
 .org $8000
@@ -101,8 +113,9 @@ reset:
 	ldx.w #$FFFF	; Reset the stack pointer.
 	txs		;
 	ldy #0		; Reset the Y register.
+	sty end		;
 	tyx		; Reset the X register.
-	lda #23		; Set the end of the screen back to 23.
+	lda #maxrow	; Set the end of the screen to the screen's max row count.
 	sta scr_end	;
 	lda.w #buffer	; Place the address for the screen buffer
 	sta.q ptr5	; into one of the pointers.
@@ -112,6 +125,7 @@ reset:
 	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		;
 	jsl clr_buf	; Clear the screen buffer.
 	jmp start	; Goto the start of the main program.
 clr_buf:
@@ -143,8 +157,7 @@ clr_buf_end:
 
 start:
 	lda #0		; TODO: Update this for the Super VIA.
-	sta end		;
-	sta $C000	; Clear the controll register of the I/O adapter.
+	sta status	; Clear the controll register of the I/O adapter.
 	tax		; Reset X.
 	phy #2		; Save the cursor index for later.
 	tay		; Reset the cursor index.
@@ -153,14 +166,15 @@ start:
 	lda.w #string	; Print the startup message.
 	jsl print_str	;
 	lda.w zero	; Reset the Accumulator.
+	sta end		;
 	jmp read	; Start reading the keyboard.
 
 clr_cbuf:
 	phb #1		; Start of callee preservation.
 	ldb #0		; Reset the B register.
-	lda.w #cmd_buf+8;
-	sta.q ptr4	;
-	tba		;
+	lda.w #cmd_buf+8; Place the address of the command buffer, plus eight
+	sta.q ptr4	; into the fourth pointer.
+	tba		; Set the Accumulator back to zero.
 clr_cbuf_st:
 	cpy.w #$3FF	; Did we clear all of the command buffer?
 	bcs clr_cbuf_nd	; Yes, so we're done.
@@ -182,7 +196,10 @@ clr_cbuf_nd:
 	rtl		; End of clr_cbuf.
 
 read:
-	lda $C000	; Did we get a key?
+	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.
 	jsl getchar	; Yes, and was it a newline?
 	beq parse	; Yes, so start parsing the line.
@@ -194,17 +211,16 @@ print_str:
 	tba		; Clear the Accumulator.
 	inb		; Enable replace mode.
 	stb b		;
-pntstr_st:
+pntstr_lp:
 	phy #2		; Save the cursor index.
 	txy		; Copy the string index into Y.
-	lda (ptr), y	; Are we at the end of the string?
-	beq pntstr_end	; Yes, so we're done.
-	ply #2		; No, so get the cursor index back.
-	inx		; Increment the string index.
+	lda (ptr), y    ; Are we at the end of the string?
+	ply #2          ; Get the cursor index back.
+	beq pntstr_end  ; Yes, so we're done.
+	inx             ; No, so increment the string index.
 	jsl print_char	; Print the character.
-	jmp pntstr_st	; Keep looping.
+	jmp pntstr_lp	; Keep looping.
 pntstr_end:
-	ply #2		; Get the cursor index back.
 	ldb #0		; Enable insert mode.
 	stb b		;
 	rtl		; End of print_str.
@@ -265,67 +281,80 @@ bitpos:
 	rtl		; End of bitpos.
 
 getchar:
-	lda $C002	; Get typed character.
-	ldb #0		;
-	stb e		;
-	stb b		;
-	pha #1		;
-	phy #2		;
-	cmp #10		;
-	beq cmd_cpy	;
+	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 #1		; Save the character.
+	phy #2		; Save the cursor index.
+	cmp #10		; Was the character that was typed, a newline?
+	beq cmd_cpy	; Yes, so start copying the line to the command buffer.
 getchar_pnt:
-	ply #2		;
-	pla #1		;
-	ldb e		;
-	bne reset_row	;
+	ply #2		; Get back the cursor index.
+	pla #1		; Get back the character.
+	ldb e		; Is the temporary row position non zero?
+	bne reset_row	; Yes, so reset the row positon.
 getchar_pt1:
-	jsl print_char	;
-	lda a		;
-	cmp #10		;
-	beq getchar_ln	;
-	jmp getchar_chr	;
+	jsl print_char	; No, so print the character.
+	lda a		; Get the return value.
+	cmp #10		; Is the return value, a newline?
+	beq getchar_ln	; Yes, so return 0.
+	jmp getchar_chr	; No, so return 1.
 reset_row:
-	ldb e		;
-	cpb #23		;
-	beq reset_row2	;
-	bcs reset_row1	;
-	jmp reset_row2	;
+	ldb e		; Get the temporary row position.
+	cpb #maxrow	; Is temporary row position, at, or above the bottom of the screen?
+	beq reset_row2	; Yes, so leave it as is.
+	bcs reset_row1	; No, so set it to the bottom of the screen.
+	jmp reset_row2	; Yes, so leave it as is.
 reset_row1:
-	ldb #23		;
+	ldb #maxrow	; Set the row position to the bottom of the screen.
 reset_row2:
-	stb scr_row	;
-	jmp getchar_pt1	;
-
+	stb scr_row	; Set the row position.
+	jmp getchar_pt1	; Print the character.
 cmd_cpy:
-	lda scr_row	;
-	sta scr_trow	;
-	jsl findend	;
-	sta scr_row	;
-	sta e		;
-	jsl findst	;
-	clc		;
-	lda scr_row	;
-	adc scr_str	;
-	mul #80		;
-	tay		;
-	ldx.w #$0	;
-cmd_cpy_st:
-	lda (ptr5), y	;
-	beq getchar_pnt	;
-	phy #2		;
-	txy		;
-	sta (ptr6), y	;
-	inx		;
-	ply #2		;
-	iny		;
-	jmp cmd_cpy_st	;
+	lda scr_row	; Get the row position.
+	sta scr_trow	; Save it for later.
+	jsl findend	; Find the end of the line.
+	sta scr_row	; Set the row position to the end of the line.
+	sta e		; Save it into the temporary row posiition.
+	jsl findst	; Find the start of the line.
+	clc		; Clear the carry flag.
+	lda scr_row	; Get the row position.
+	adc scr_str	; Add it with the screen's starting row.
+	mul #maxcol+1	; Multiply it with the width of the screen, plus one.
+	tay		; Place it into the index.
+	ldx.w #0	; Reset the X register.
+cmd_cpy_lp:
+	ldb #0		; Reset the B register.
+	lda.q (ptr5), y	; Get eight bytes from the current line.
+cmd_cpy_lp1:
+	phy #2		; Save the screen index.
+	txy		; Get the command buffer index.
+	sta (ptr6), y	; Copy one byte from the screen buffer, to the command buffer.
+	inx		; Increment the command buffer index.
+	ply #2		; Get back the screen index.
+	iny		; Increment the screen index.
+	inb		; Increment the byte count.
+	lsr #8		; Shift in the next byte.
+	stb g		; Save the byte count.
+	tab		; Save the string buffer.
+	and #$FF	; Is this byte of the buffer, a null terminator?
+	beq cmd_cpy_nd	; 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 cmd_cpy_lp	; Yes, so get eight more bytes.
+	jmp cmd_cpy_lp1	; No, so keep shifting in more bytes.
+cmd_cpy_nd:
+	tab		; The B register is zero, so clear the Accumulator.
+	jmp getchar_pnt	; Go back to printing the character.
 getchar_ln:
-	lda #0		;
-	jmp getchar_end	;
+	lda #0		; Return zero.
+	jmp getchar_end	; We are done.
 getchar_chr:
-	lda #1		;
+	lda #1		; Return one.
 getchar_end:
-	rtl		;
+	rtl		; End of get char.
 
 findst:
 	lda #0		;
@@ -358,7 +387,7 @@ fndend_done:
 findend:
 	jsl fndend	;
 	lda.w scr_ptr3	;
-	div #80		;
+	div #maxcol+1	;
 	rtl		;
 
 parse:
@@ -374,7 +403,7 @@ print_char:
 	sta a		;
 	cmp #$1B	;
 	beq esc		;
-	cmp #$A		;
+	cmp #10		;
 	beq nl		; Did the user type a newline?
 	cmp #$C		;
 	beq clr_scr	;
@@ -444,32 +473,33 @@ printc_2:
 	ldb #1		;
 	stb f		;
 	ldb scr_col	;
-	cpb #80		;
+	cpb #maxcol+1	;
 	bcs printc_4	;
 printc_3:
-	sta $C001	; Echo typed character.
+	sta scr		; Echo typed character.
 	ldb f		;
 	beq printc_wrap	;
 	jmp printc_end	;
 printc_4:
 	ldb scr_row	;
-	cpb #23		;
+	cpb #maxrow	;
 	bcs printc_scrl	;
 printc_5:
 	ldb #0		;
 	stb f		;
 	jmp printc_3	;
 printc_scrl:
-	sta $C001	; Echo typed character.
+	sta scr		; Echo typed character.
 	clc		;
 	lda #1		;
 	sta wrapped	;
 	jsl scrl_down	;
+	jmp printc_wrap	;
 printc_wrap:
-	ldb #0		;
+	ldb #0
 	stb scr_col	;
 	ldb scr_row	;
-	cpb #23		;
+	cpb #maxrow	;
 	bcs printc_wrp2	;
 printc_wrap1:
 	inc scr_row	;
@@ -493,7 +523,7 @@ nl:
 nl1:
 	sta scr_col	;
 	lda scr_row	;
-	cmp #23		;
+	cmp #maxrow	;
 	bcc nl_inc	;
 	jsl scrl_down	;
 	lda #10		;
@@ -507,7 +537,7 @@ nl_inc:
 	jmp printc_end	;
 
 clr_scr:
-	lda #23		;
+	lda #maxrow	;
 	sta scr_end	;
 	lda #0		;
 	sta scr_str	;
@@ -521,25 +551,25 @@ clr_scr:
 	sta scr_row	;
 	jsl update_pos	;
 	lda #$C		;
-	sta $C001	;
+	sta scr		;
 	jmp printc_end	;
 
 en_step:
-	lda $C010	;
+	lda step	;
 	beq step_en	;
 	jmp printc_end	;
 step_en:
 	lda #1		;
-	sta $C010	;
+	sta step	;
 	jmp printc_end	;
 
 dis_step:
-	lda $C010	;
+	lda step	;
 	bne step_dis	;
 	jmp printc_end	;
 step_dis:
 	lda #0		;
-	sta $C010	;
+	sta step	;
 	jmp printc_end	;
 
 back:
@@ -566,7 +596,7 @@ back1:
 	stb d		;
 	jsl shftln	; Shift line back by one character.
 	lda #$7F	; Print a backspace to the screen.
-	sta $C001	;
+	sta scr		;
 	lda e		;
 	beq back3	;
 back2:
@@ -617,7 +647,7 @@ backwrp:
 backwrp2:
 	dec scr_row	; Move up by one row.
 ;	jsl clrbit	; Clear the wrap bit for this row.
-	ldb #80		; Move the cursor to the absolute right of the screen.
+	ldb #maxcol+1	; Move the cursor to the absolute right of the screen.
 	stb scr_col	;
 	jsl update_pos	; Update the cursor's position.
 	jmp back	; Delete the previous character.
@@ -691,9 +721,9 @@ shftln_nd1:
 shftln_end1:
 	jsl findend	; Find the ending line.
 	cpb #0		; Is the remainder zero?
-	beq shftln_nd01	; Yes, so check if the ending line is greater than the starting line.
+	beq shftln_nd2	; Yes, so check if the ending line is greater than the starting line.
 	jmp shftln_end2	; No, so we're done.
-shftln_nd01:
+shftln_nd2:
 	cmp scr_row	; Is the ending line greater than the starting line?
 	beq shftln_end2	; No, so we're done.
 	bcs shftln_wrp1	; Yes, so clear the wrap bit.
@@ -701,13 +731,13 @@ shftln_end2:
 	rtl		; End of shftln.
 
 esc:
-	lda $C000	; Get the next character.
-	lda $C002	;
+	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 $C000	; No, so wait for the next character.
+	lda status	; No, so wait for the next character.
 	beq printc_end	; We have an error, so discard it, and go back to getting user input.
-	lda $C002	; Get the escape code.
+	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		;
@@ -728,10 +758,11 @@ esc_end:
 	jmp printc_end	; We are done.
 
 shftesc:
-	lda $C000	; Skip the '['.
-	lda $C000	; Get the next character.
+	lda status	; Skip the '['.
+	lda kbd		;
+	lda status	; Wait for the next character.
 	beq printc_end	; We have an error, so discard it, and go back to getting user input.
-	lda $C002	; Get the escape code.
+	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		;
@@ -769,7 +800,7 @@ isdown:
 	cmp #$42	; Did the user press the down arrow key?
 	bne isdown_done	; No, so we're done.
 	lda scr_row	; Yes, so start checking the y coordinate of the cursor.
-	cmp #23		; Is the cursor at the bottom of the screen?
+	cmp #maxrow	; Is the cursor at the bottom of the screen?
 	beq isdown_scrl	; Yes, so scroll down.
 	lda c		; No, so load the escape code back into the accumulator.
 	cmp #$42	; Did the user press the down arrow key?
@@ -795,7 +826,7 @@ isright:
 	cmp #$43	; Did the user press the right arrow key?
 	bne isright_dne	; No, so we're done.
 	lda scr_col	; Yes, so start checking the x coordinate of the cursor.
-	cmp #79		; Is the cursor at the far right of the screen?
+	cmp #maxcol	; Is the cursor at the far right of the screen?
 	beq isright_wrp	; Yes, so check if this is a wrapped line.
 	jmp right	; No, so move the cursor right, like normal.
 isright_wrp:
@@ -815,7 +846,7 @@ wrap_inc:
 	lda #0		; Set the cursor to the far left of the screen.
 	sta scr_col	;
 	lda scr_row	; Get the current row number.
-	cmp #23		; Are we at the bottom of the screen?
+	cmp #maxrow	; Are we at the bottom of the screen?
 	beq isright_nd2	; No, so we're done.
 	bcs isright_scr	; Yes, so check if we are scrolling down.
 	jmp isright_nd2	; No, so we're done.
@@ -849,7 +880,7 @@ wrap_dec:
 	sta wrapped	;
 	dec scr_row	; Move the cursor up one line.
 wrap_dec1:
-	lda #79		; Move the Cursor to the far right of the screen.
+	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		;
@@ -937,58 +968,52 @@ update_pos:
 	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.
-	clc		; Clear the carry flag.
-	lsl #6		; Multiply the absolute line number by 64.
-	tab		; Use it as a second operand.
-	tya		; Place the absolute line number back into the Accumulator
-	lsl #4		; Multiply the absolute line number by 16.
-	aab		; Add both the Accumulator, and the B register together, to multiply the line number by 80.
-	clc		; Clear the carry flag.
+	mul #maxcol+1	; Multiply the line number by the screen's max column count, plus 1.
 	adc scr_col	; Add the cursor's column number to get the screen index.
 	tay		; Place the index into the Y register.
 	lda #$1B	; Print an escape character
-	sta $C001	; to the screen.
+	sta scr		; to the screen.
 	lda #$5B	; Print '['
-	sta $C001	; to the screen, and start the escape sequence.
+	sta scr		; to the screen, and start the escape sequence.
 	jsl getrow	; Start printing the row number to the screen.
 	jsl getcol	; Start printing the column number to the screen.
 	lda #$48	; Print 'H'
-	sta $C001	; to the screen.
+	sta scr		; to the screen.
 	rtl		; End of update_pos.
 
 getrow:
 	lda scr_row	; Get the cursor's y coordinate.
 	div #10		; Divide A by 10.
 	adc #$30	; Convert it to ascii, and
-	sta $C001	; print to the screen.
+	sta scr		; print to the screen.
 	tba		; Get the remainder.
 	adc #$30	; Convert it to ascii, and
-	sta $C001	; print to the screen.
+	sta scr		; print to the screen.
 	rtl		; End of getrow.
 
 getcol:
 	lda #$3B	; Print ';'
-	sta $C001	; to the screen.
+	sta scr		; to the screen.
 	lda scr_col	; Get the cursor's x coordinate.
 	div #10		; Divide A by 10.
 	clc
 	adc #$30	; Convert it to ascii, and
-	sta $C001	; print to the screen.
+	sta scr		; print to the screen.
 	tba		; Get the remainder.
 	clc
 	adc #$30	; Convert it to ascii, and
-	sta $C001	; print to the screen.
+	sta scr		; print to the screen.
 	rtl		; End of getrow.
 
 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 $C001	; to the screen.
+	sta scr		; to the screen.
 	lda #$5B	; Print '['
-	sta $C001	; to the screen, and start the escape sequence.
+	sta scr		; to the screen, and start the escape sequence.
 	lda #$54	; Print 'T'
-	sta $C001	; to the screen, and end the escape sequence.
+	sta scr		; to the screen, and end the escape sequence.
 	lda scr_row	; Get the cursor's line number.
 	pha #1		; Save it in the stack.
 	lda wrapped	; Was the wrapped flag set?
@@ -1018,11 +1043,11 @@ scrl_up:
 	dec scr_str	;
 	dec scr_end	;
 	lda #$1B	; Print an escape character
-	sta $C001	; to the screen.
+	sta scr		; to the screen.
 	lda #$5B	; Print '['
-	sta $C001	; to the screen, and start the escape sequence.
+	sta scr		; to the screen, and start the escape sequence.
 	lda #$53	; Print 'S'
-	sta $C001	; to the screen, and end the escape sequence.
+	sta scr		; to the screen, and end the escape sequence.
 	lda scr_row	;
 	pha #1		;
 	lda scr_col	;
@@ -1045,7 +1070,7 @@ rdrw_row:
 rdrow_st:
 	lda (ptr5), y	;
 	beq rdrow_inc	;
-	sta $C001	;
+	sta scr		;
 rdrow_inc:
 	inc scr_col	;
 	lda (ptr5), y	;
@@ -1054,12 +1079,12 @@ rdrow_inc1:
 	iny		;
 rdrow_inc2:
 	lda scr_col	;
-	cmp #80		;
+	cmp #maxcol+1	;
 	bcs rdrow_end	;
 	jmp rdrow_st	;
 rdrow_skip:
 	lda #$20	;
-	sta $C001	; to the screen.
+	sta scr		; to the screen.
 	jmp rdrow_inc1	;
 rdrow_end:
 	lda #0		;
@@ -1080,7 +1105,7 @@ rset_x:
 dabbed:
 	ldb #0		;
 	lda.w #tok	;
-	sta.q ptr2	;
+	sta.q ptr2	;i
 	tba		;
 dab_st:
 	phy #2		;
@@ -1124,7 +1149,6 @@ cmd_clr:
 rdrw_ln:
 	lda scr_row	;
 	pha #1		;
-	inc end		;
 	lda f		;
 	sta scr_row	;
 	lda scr_col	;
@@ -1149,13 +1173,11 @@ rdrwln_done:
 	lda #0		;
 	sta e		;
 	sta f		;
-	dec end		;
 	rtl		;
 
 
 .org $FFC0
 .qword reset
-
 a
 done