Table of Contents

Overview
Store
Load

Overview

This file has the routines to store and load values. Currenlty values can only be stored from the result and loaded into number1 and number 2.
Currently, only one number can be stored at a time.

Store

Here is the routine that Stores a value from the result into memory:

; assumes that diplayed result always matches wResult (except if wResultError is set)
StoreVal::

	ld a,[wResultError]
	or a,a ; set flags
	jr nz, .end ; exit if last calc had an error


	; load value into BC
	ld a,[wResult]
	ld c,a
	ld a,[wResult+1]
	ld b,a

	; check if result is positive
	ld a,[wResultNegative]
	or a,a ; set the flags based on the value of a
	jp z,.positive

	call negateBC ; make negative if number is negative

	.positive:
	;store value
	ld a,c
	ld [wStoredNumber0],a
	ld a,b
	ld [wStoredNumber0+1],a

	.end:
	ret

Load

The Load routine uses the cursor state to see what to do.
If the cursor is on one of the numbers, it puts the value into there. There is some code duplication, but its fine for now. It needs to temporarily load the value into wResult to work with the Double Dabble Routine

LoadVal::

	;check what value to load into

	ld a,[wCursorState]
	
	cp a,1 ; if cursor on number0
	jr z, .loadIntoNumber0

	cp a,4 ; if cursor on number1
	jr z, .loadIntoNumber1

	; if somewhere else
	ret

	.loadIntoNumber0:
	
	; WORKAROUND, BECAUE BCD ONLY WORKS WITH RESULT VARIABLE

	;backup result
	ld a,[wResult]
	ld [wTmpNumber],a
	ld a,[wResult+1]
	ld [wTmpNumber+1],a

	; load number 1 into result
	ld a,[wStoredNumber0]
	ld [wResult],a
	ld a,[wStoredNumber0+1]
	ld [wResult+1],a
	
	call prepareResult ; do bcd
	call adjutsBCD


	; do display stuff here:

	call waitStartVBlank 

	ld a,[wStoredNumber0+1] ; if the number is positve, skip to .positive
	and a, %1000_0000 ; only keep sign
	jp z,.positive0

	;number negative

	; write a '-' before the number
	ld a,tile_sub
	ld [screen+num0_prefixI],a
	jp .printNum0

	.positive0: ; write a '+' before the number
	ld a,tile_add
	ld [screen+num0_prefixI],a

	.printNum0:


	ld DE,wDoubleDabble ; SOURCE
	ld HL,screen + num0I ; DESTINATION
	ld BC,doubleDabbleSize ; BYTES
	call Memcpy

	;jr .exit


	jr .exit


	.loadIntoNumber1:
	
	; WORKAROUND, BECAUE BCD ONLY WORKS WITH RESULT VARIABLE

	;backup result
	ld a,[wResult]
	ld [wTmpNumber],a
	ld a,[wResult+1]
	ld [wTmpNumber+1],a

	; load number 1 into result
	ld a,[wStoredNumber0]
	ld [wResult],a
	ld a,[wStoredNumber0+1]
	ld [wResult+1],a
	
	call prepareResult ; do bcd
	call adjutsBCD


	; do display stuff here:

	call waitStartVBlank 

	ld a,[wStoredNumber0+1] ; if the number is positve, skip to .positive
	and a, %1000_0000 ; only keep sign
	jp z,.positive1

	;number negative

	; write a '-' before the number
	ld a,tile_sub
	ld [screen+num1_prefixI],a
	jp .printNum1

	.positive1: ; write a '+' before the number
	ld a,tile_add
	ld [screen+num1_prefixI],a

	.printNum1:


	ld DE,wDoubleDabble ; SOURCE
	ld HL,screen + num1I ; DESTINATION
	ld BC,doubleDabbleSize ; BYTES
	call Memcpy

	;jr .exit

	.exit:

	;restore result variable
	ldh a,[wTmpNumber]
	ld [wResult],a
	ldh a,[wTmpNumber+1]
	ld [wResult+1],a

	ret