path: root/programs/sub-suite/subasm.s

; SuBAsm
; The Sux Bootstrapped Assembler.
;
; by mr b0nk 500 <b0nk@b0nk.xyz>

;subasm:
;	ldb #0		; Set the first pointer
;	lda.q cmd_buf	; to the command buffer.
;	jsr set_ptr	;
;	tba		; Reset A.
;	tax		; Reset X.
;	jsr chk_shcmd	; Did we get a shortend command?
;	bne @cmd	; Yes, so skip everything else.
;	jsr chk_cmd	; No, but did we get a full command?
;	bne @cmd	; Yes, so skip everything else.
;	jsr lex		; No, so start lexing this line.
;	bra @end	; We are done.
;@cmd:
;	lda regf	; Get the command ID.
;	cmp #8		; Is the command ID greater than the command count?
;	bcs @end	; Yes, so we're done.
;	lsl #1		; No, so multiply the command ID by two.
;	phx.q		; Preserve X.
;	tax             ; Set the index to the offset that we just calculated.
;	lea.w (cmd_srt, x); Get the pointer, from the command subroutine table.
;	plx.q		; Restore X.
;	and #0		; Reset A.
;	tab		; Reset B.
;	jsr (e)		; Run the command's subroutine.
;@end:
;	and #0		; Reset A.
;	jsr update_ptr	; Get the screen buffer index.
;	tay		; Save it in Y.
;	and #0		; Reset A.
;	rts		; End of subasm.
;
;chk_shcmd:
;	and #0		; Reset A.
;	tab		; Reset B.
;;	inb		; Set the second pointer
;;	lda.w #sh_cmds	; to the shortend command table.
;;	jsr set_ptr	;
;;	deb		; Reset B.
;;	tba		; Reset A.
;	lea sh_cmds	; Get the address of the short command table.
;	phy.w		; Preserve the screen buffer position.
;	txy		; Set our index to zero.
;	lda (ptr), y	; Is there nothing in the command buffer?
;	beq @false	; Yes, so return that we failed.
;	cmp #' '	; No, but is this character, a space?
;	beq @false	; Yes, so return that we failed.
;	jsr tolower	; No, so convert it to lowercase.
;@loop:
;;	ldb (ptr2), y	; Are we at the end of the table?
;	ldb (e)		; Are we at the end of the table?
;	beq @false	; Yes, so return that we failed.
;	cmp b		; No, so did the character match?
;	beq @found	; Yes, so check if there are any arguments.
;	ine		; No, so check the next command.
;	iny		;
;	bra @loop	; Keep looping.
;@found:
;	sty regf	; Save the command ID.
;	lea (ptr)	; Get the address of the next character.
;	ine		;
;;	ldy #1		; Check the next character in the command buffer.
;;	lda (ptr), y	; Is this the end of the buffer?
;	lda (e)		; Is this the end of the buffer?
;	beq @true	; Yes, so return true.
;	cmp #' '	; No, but is this a space?
;	beq @true	; Yes, so return true.
;@false:
;	ldb #0		; Reset B.
;	tba		; Return false.
;	tax		; Reset X.
;	bra @end	; We are done.
;@true:
;	lda #1		; Return true.
;@end:
;	ply.w		; Get back the screen buffer position.
;	rts		; End of chk_shcmd.
;
;
;chk_cmd:
;	and #0		; Reset A.
;	tab		; Reset B.
;	tax		; Reset X.
;	sta.q idx0	; Reset the first index.
;	sta.q idx1	; Reset the second index.
;	mov.q ptr, d	; Set the first pointer to the command buffer.
;@loop:
;	lda.w #cmds	; Get pointer to the start of the command table.
;	add.w idx0	; Offset the pointer, by the length of the previous string.
;	pha.q		; Preserve the command string pointer.
;	jsr strcaseg	; Is the command buffer, the same as the command string?
;	pla.q		; Get the command string pointer back.
;	beq @true	; Yes, so return true.
;	ldb idx1	; No, so Get the command ID.
;	cpb #7		; Have we reached the end of the command table?
;	beq @false	; Yes, so return false.
;	inc idx1	; No, so increment the command ID.
;@getlen:
;	mov d, a	; Get the string.
;	jsr strlen	; Get the string's length.
;	inc		; Add one to the length.
;	add.w idx0, a	; Add the string offset to the current length
;	bra @loop	; Keep looping.
;@true:
;	ldb idx1	; Get the command ID.
;	stb regf	; Return the command ID.
;	ldb #1		; Return true.
;	bra @end	; We are done.
;@false:
;	ldb #0		; Return false.
;@end:
;	rts		; End of chk_cmd.


subasm:
	pha.q			; Preserve A.
	des			; Make room for the command id.
	and #0			; Reset A.
	lea d, (cmd_buf)	; Get the command buffer.
	lea s, (sp+1)		; Get the pointer to the command id.
	jsr chk_shcmd		; Did we get a shortend command?
	bne @cmd		; Yes, so skip everything else.
	jsr chk_cmd		; No, but did we get a full command?
	bne @cmd		; Yes, so skip everything else.
	mov.q ptr, d		;
	psh d			; Preserve D.
	psh s			; Preserve S.
	psh f			; Preserve F.
	jsr lex			; No, so start lexing this line.
	pul d			; Restore D.
	pul s			; Restore S.
	pul f			; Restore F.
	bra @end		; We are done.
@cmd:
	mov s, (s)		; Get the command ID.
	cmp s, #7		; Is the command ID greater than the command count?
	bcs @end		; Yes, so we're done.
;	lsl s, #1		; No, so multiply the command ID by two.
;	lea.w s, (cmd_srt+s)	; Get the pointer, from the command subroutine table.
	lea b, cmd_srt		; No, so get the address of the command subroutine table.
	mov.w s, (b+2*s)	; Get the pointer, from the command subroutine table.
	and #0			; Reset A.
	tab			; Reset B.
	jsr s			; Run the command's subroutine.
@end:
	and #0			; Reset A.
	jsr update_ptr		; Get the screen buffer index.
	tay			; Save it in Y.
	ins			; Cleanup the stack frame.
	pla.q			; Restore A.
	rts			; End of subasm.


chk_shcmd:
	phb.q			; Preserve B.
	lea b, sh_cmds		; Get the address of the short command table.
	mov a, (d)		; Is the string empty?
	beq @false		; Yes, so return that we failed.
	cmp #' '		; No, but is this character, a space?
	beq @false		; Yes, so return that we failed.
	jsr tolower		; No, so convert it to lowercase.
@loop:
	cmp (b), #0		; Are we at the end of the table?
	beq @false		; Yes, so return that we failed.
	cmp a, (b)		; No, so did the character match?
	beq @found		; Yes, so check if there are any arguments.
	inb			; No, so check the next command.
	bra @loop		; Keep looping.
@found:
	sub.w b, #sh_cmds	; Get the command ID.
	mov (s), b		; Save the command ID.
	mov a, (d+1)		; Is this the end of the string?
	beq @true		; Yes, so return true.
	cmp #' '		; No, but is this a space?
	beq @true		; Yes, so return true.
@false:
	and #0			; Return false.
	bra @end		; We are done.
@true:
	lda #1			; Return true.
@end:
	plb.q			; Restore B.
	rts			; End of chk_shcmd.


chk_cmd:
	phb.q			; Preserve B.
	phx.q			; Preserve X.
	phy.q			; Preserve Y.
	and #0			; Reset A.
	tab			; Reset B.
	mov x, s		; Preserve the command ID pointer.
	mov y, d		; Preserve the string pointer.
	lea s, cmds		; Get pointer to the start of the command table.
@loop:
	jsr strcasecmp		; Is the command buffer, the same as the command string?
	beq @true		; Yes, so return true.
	inb			; No, so increment the command ID.
	cpb #7			; Have we reached the end of the command table?
	bcs @false		; Yes, so return false.
@getlen:
	mov d, s		; Get the command table string.
	jsr strlen		; Get the string's length.
	mov d, y		; Restore the string pointer.
	inc			; Add one to the length.
	add s, a		; Add the string offset to the current length
	bra @loop		; Keep looping.
@true:
	lda #1			; Return true.
	bra @end		; We are done.
@false:
	lda #0			; Return false.
@end:
	mov s, x		; Restore the command ID pointer.
	mov (s), b		; Save the command ID.
	and a, a		; Set the flags accordingly.
	ply.q			; Restore Y.
	plx.q			; Restore X.
	plb.q			; Restore B.
	rts			; End of chk_cmd.


viewmem:
	pha.q			; Preserve A.
	phb.q			; Preserve B.
	phx.q			; Preserve X.
	sbs #$50		; Make room for the string buffer.
	and #0			; Reset A.
	tab			; Reset B.
	ldx.q prg_cnt		; Get the program counter.
	lda #19			; Move the cursor to the right, by 19 columns.
	sta scr_col		;
	jsr update_pos		;
	jsr print_lo		; Print the low nibble offsets.
@loop:
	lda #'\n'		; Print a newline.
	jsr print_char		;
	lea d, (sp+1)		; Get the address of the string buffer.
	mov s, x		; Get the program counter.
	jsr print_hi		; Print the address to the string buffer.
	mov d, a		; Get the string buffer pointer after the printed address.
	mov s, x		; Get the program counter.
	jsr print_chunk		; Print the next 16 bytes to the string buffer.
	lea d, (sp+1)		; Get the address of the string buffer.
	lea s, (buffer)+y	; Get the address of the screen buffer, at the current cursor position.
;	jsr print_str		; Print the string buffer.
	jsr print_sfast		;
	inb			; Increment the chunk count.
	cpb #$10		; Did we print 16 chunks?
	beq @end		; Yes, so we're done.
	add x, #$10		; No, so add 16 to the address.
	and #0			; Reset A.
	bra @loop		; Keep looping.
@end:
	lda #'\n'		; Print a newline.
	jsr print_char		;
	ads #$50		; Cleanup the stack frame.
	plx.q			; Restore X.
	plb.q			; Restore B.
	pla.q			; Restore A.
	rts			; End of viewmem.


list:
	nop		;
@end:
	rts		; End of list.
asm:
	nop		;
@end:
	rts		; End of asm.
help:
	nop		;
@end:
	rts		; End of help.
instruction:
	nop		;
@end:
	rts		; End of instruction.
run:
	nop		;
@end:
	rts		; End of run.
set_val:
	nop		;
@end:
	rts		; End of set_val.