.include hwdefs.asm

.define CursorBlinkTicks 20

.org SYSROM
	lds stack
	ldv interrupt
	ldp screen.char
	
	jss clearscreen
	
	lda 0
	sta *cursorTimer
	
	{
		lda 1
		sta *io.timer
		hlt
		jss handleKeys
		jss blinkCursorTick
	jpr }
	
	;-----------
	
	FUNC / { / irt
		interrupt:
		;stp *inttempp
		;ldp s / stp *inttemps
		;lds intstack
		;psh f / psh a / psh b / psh c / psh q
		
		run
		
		;pop q / pop c / pop b / pop a / pop f
		;ldp *inttemps / lds p
		;ldp *inttempp
	jpr }
	
	FUNC handleKeys:
		lda *keyboard.queue
		jpz {
			jss keypressed
			jpr handleKeys
		}
	rts
	
	FUNC blinkCursorTick:
		lda *cursorTimer
		jnz {
			ldp *screenPos
			ldc ph / ldb pl / adc $04 / ldp cb ; get color addr from screen pos
			;lda *p / xor $80 / sta *p ; toggle highlight bit
			lda *p / xor $03 / sta *p ; toggle black/white
			
			lda CursorBlinkTicks
		}
		dec a
		sta *cursorTimer
	rts
	
	FUNC numshifts: ")!@#$%^&*("
	FUNC keys_2430:         ";=,.-/`"
	FUNC keys_2430_shift:   ":+<>_?~"
	FUNC keys_6063:         "[\\]'"
	FUNC keys_6063_shift:   "{|}\""
	FUNC keys_numpad:       "0123456789*+\n-./"
	FUNC keys_numpad_shift: "0123456789*+\n_.?"
	
	FUNC keypressed: ; key in a
		ldb a
		
		; check for shift
		and $7F
		cmp $10 / jpz keyShift / cmp $14 / jnz keyNoShift
			keyShift:
				lda b / and $80 / shr 7 / sta *shiftDown
				rts
		keyNoShift:
		
		lda b
		and $80
		jnz { / rts / }
		
		lda b
		and $7F
		; ldp *screenPos / sta *p++ / stp *screenPos
		; jss printhex / lda b
		cmp "A" / jlt { / cmp "Z" / jgt { ; letter
			ldb *shiftDown / jnz {
				add $20
			}
			jss printchar
			rts
		} / }
		cmp "0" / jlt { / cmp "9" / jgt { ; number
			ldb *shiftDown / jpz {
				sub "0" / ldb a / ldp numshifts / adp b
				lda *p
			}
			jss printchar
			rts
		} / }
		ldp keys_2430 / ldq keys_2430_shift / ldb 24 / ldc 30 / jss printcharblock ; symbols
		ldp keys_6063 / ldq keys_6063_shift / ldb 60 / ldc 63 / jss printcharblock
		ldp keys_numpad / ldq keys_numpad_shift / ldb 96 / ldc 111 / jss printcharblock
		cmp 13 / jnz { ; newline
			jss clearCursor
			ldp *screenPos
			ldb pl / ldc ph
			lda b / and $C0 / ldb a
			ldp cb
			adp $40
			stp *screenPos
			jss updateMoveScreen
			rts
		}
		cmp 9 / jnz { ; tab
			
			rts
		}
		cmp 32 / jnz { / lda 32 / jsr printchar / rts / } ; space
		cmp 8 / jnz { ; backspace
			ldc 1 / jss moveback
			rts
		}
		cmp 37 / jnz { ; left
			ldc 0 / jss moveback
			rts
		}
		cmp 39 / jnz { ; right
			jss clearCursor
			ldp *screenPos
			lda ph / cmp $0B / jnz {
				lda pl / cmp $FF / jnz {
					rts
				}
			}
			adp 1
			stp *screenPos
			rts
		}
		jss printhex
	rts
	
	FUNC moveforward:
		
	rts
	
	FUNC moveback: ; c = delete char (bool)
		jss clearCursor
		ldp *screenPos
		lda ph / cmp $08 / jnz {
			lda pl / tst a / jnz {
				rts
			}
		}
		adp -1
		lda *p / jpz { ; one character
			tst c / jpz {
				lda 0 / sta *p
			}
			stp *screenPos
		jpr | ; blank line
			{
				lda pl / and $3F ; stop at beginning of line
				adp -1
				jpz |
				lda *p
			jpz }
			adp 1
			stp *screenPos
		}
	rts
	
	FUNC printcharblock:
		cmp b / jlt { / cmp c / jgt {
			ldc *shiftDown / jpz {
				ldp q
			}
			sub b / ldb a / adp b
			lda *p / jss printchar
			pop q / rts
		} / }
	rts
	
	FUNC clearCursor:
		psh a / psh b / psh c
		ldp *screenPos
		ldc ph / ldb pl / adc $04 / ldp cb ; get highlight addr from screen pos
		;lda *p / and $7F / sta *p ; clear highlight bit
		lda $3E / sta *p ; set to black
		lda 0 / sta *cursorTimer
		pop c / pop b / pop a
	rts
	
	FUNC updateMoveScreen:
		ldp *screenPos
		lda ph
		cmp $0C
		jnz {
			jss moveScreenUp
		}
	rts
	
	FUNC printchar:
		jss clearCursor
		ldp *screenPos / sta *p++ / stp *screenPos
		jss updateMoveScreen
	rts
	
	FUNC moveScreenUp:
		ldp (SCREEN+$40)
		ldq (SCREEN)
		ldb $0F / {
			ldc $40 / {
				lda *p++ / sta *q++
				dec c
			jnz }
			dec b
		jnz }
		stq *screenPos
		ldb $00
		ldc $20
		ldp (SCRCLR+$40*$0F)
		lda $40 / {
			stb *q++
			stc *p++
			dec a
		jnz }
	rts
	
	FUNC printhex:
		ldp *screenPos
		ldb a
		and $F0
		shr 4
		add "0"
		cmp "9" / jle { / add 7 / }
		jss printchar
		lda b
		and $0F
		add "0"
		cmp "9" / jle { / add 7 / }
		jss printchar
		lda 0
		jss printchar
		stp *screenPos
	rts
	
	FUNC clearscreen:
		ldp screen.char / stp *screenPos
		ldq screen.color
		lda $00 ; blank
		;ldb $20 ; white color, no highlight
		ldb $3E ; black color, no highlight
		ldc 128 ; 128*8 = 4k of each p and q
		{
			sta *p++
			stb *q++
			sta *p++
			stb *q++
			sta *p++
			stb *q++
			sta *p++
			stb *q++
			sta *p++
			stb *q++
			sta *p++
			stb *q++
			sta *p++
			stb *q++
			sta *p++
			stb *q++
			dec c
		jnz }
	rts

.org SYSRAM
	inttempp: word
	inttemps: word
	intstack: byte[(128-4)]
	stack: byte[128]

.org USERRAM
	screenPos: word
	shiftDown: byte
	cursorTimer: byte