X.z80 by bb94

#include    "ti83plus.inc"
#define     progStart   $9D95
.org        progStart-2
.db         $BB,$6D
    ; Input: {r, c, X}
    ; if not in this format, then exits
    ; First, get the list
    ; Second, get row and col
    ; Third, get number and store to hl
    ; Last, draw the digits
    ; WORKS FOR 8-BIT VALS
    ; bcall(_AnsName) gets the name of Ans in OP1
    ;
    bcall(_RclAns)
    and $1F ;masking
    dec a
    ret nz ;bail if not a list
    ex de,hl ;now hl has the size and de has the symentry
    ld c,(hl) ;I presume that c has the value?
    inc hl
    ld b,(hl)
    inc hl ;Thanks to Xeda for this code!
    ; "So the code I gave returns HL pointing to the data for the first element, BC is the number of elements"
    ; Checks if bc == 3
    ld a,c
    cp 3
    ret nz
    ld a,b
    or a
    ret nz ;this basically exits if the number of elements is not equal to 3
    rst rMov9ToOP1 ;What does this do?
    push hl
    bcall(_ConvOP1)
    pop hl
    ld (curRow),a
    rst rMov9ToOP1 ;What does this do?
    push hl
    bcall(_ConvOP1)
    pop hl
    ld (curCol),a
    rst rMov9ToOP1 ;What does this do?
    push hl
    bcall(_ConvOP1)
    pop hl
    ld b,a
    jr WriteHex8

    ; In:
    ;  B: the number
    ;  (curRow), (curCol): Obvious.
    ; Out:
    ;  Nothing.
    ; Destroys:
    ;  A,B,C,HL
WriteHex8:
    ld a,b
    call GetHexDigit
    push bc
    bcall(_PutC)
    pop bc
    ld a,(curCol)
    sub 2
    ld (curCol),a
    ld a,b
    rra
    rra
    rra
    rra
    call GetHexDigit
    push bc
    bcall(_PutC)
    pop bc
    ret
GetHexDigit: ; Thanks to Xeda for the optimization
    and 0Fh
    add a,30h
    cp 3Ah
    ret c
    add a,7
    ret