; --- Data Stack --- ;
; on this channel we love garth wilson: https://wilsonminesco.com/stacks/StackOps.ASM
; data stack is built up of 2-byte cells


; TODO: this is broken, jumping here does nothing to the stack and skips several instructions, could be an emulator problem tho
; push_lit: ; this bad boy lets you inline a literal (low byte first) right after `jsr push_lit` and put it on the stack, once again, on this channel we love garth wilson
;    push2
;    phx
;        tsx
;        txa
;        tay
;    plx

;    lda $102, y
;    sta 0, x
;    clc
;    adc #2
;    sta $102, y

;    lda $103, y
;    sta 1, x
;    adc #0
;    sta $103, y

; fetch: 
;     lda (0, x)
;     pha
;     inc 0, x
;     bne .1
;     inc 1, x
;     .1:     
;         lda (0, x)
;         bra put
;     push

; put:
;     sta 1, x
;     pla
;     sta 0, x
;     rts

plus: ; add: (n1 n2 -- n1+n2)
    clc
    lda 0, x
    adc 2, x
    sta 2, x
    lda 1, x
    adc 3, x
    sta 3, x
    pop
    rts


mult: ; multiply: (n1 n2 -- n1*n2), frankly, i don't know how this works, but TODO: will try to figure it out later
    phy
    stz n
    ldy #0
    .1:     
        lsr 3, x
        ror 2, x
        bcc .2
            clc
            lda n
            adc 0, x
            sta n
            tya
            adc 1, x
            tay
    .2:     
        asl 0, x
        rol 1, x
        lda 2, x
        ora 3, x
    bne .1
    lda n
    sta 2, x
    sty 3, x
    pop
    ply
    rts