;********************************************************************************
; @module math
; @type utility
; @details
;   Math library
;********************************************************************************
.ifndef INCLUDE_MATH
INCLUDE_MATH = 1

.scope math

;********************************************************************************
; @macro Divide a num (or A) by a factor
; @param num: Memory or A
; @param divider: must be power of 2
;********************************************************************************
.macro div num,divider
.if divider = 2
    lsr num
.elseif divider = 4
    lsr num
    lsr num
.elseif divider = 8
    lsr num
    lsr num
    lsr num
.elseif divider = 16
    .repeat 4
    lsr num
    .endrepeat
.elseif divider = 32
    .repeat 5
    lsr num
    .endrepeat
.elseif divider = 64
    .repeat 6
    lsr num
    .endrepeat
.elseif divider = 128
    .repeat 7
    lsr num
    .endrepeat
.else
    .error "div macro: divider % 2 != 0"
.endif
.endmacro

; .macro Amult1 factor
;     phx
;     ldx factor
;     AmultX
;     plx
; .endmacro

; https://www.llx.com/Neil/a2/mult.html
; .macro mult num1,num2,result
;     lda #0
;     ldx #8
; L1: 
;     lsr num2
;     bcc L2
;     clc
;     adc num1
; L2:
;     ror
;     ror result
;     dex
;     bne L1
;     sta result+1
; .endmacro

;         00110101
;         10010011
;         -------^
;        =00110101
;        00110101
;        01001001
;        -------^
;       =00110101
;       00110101
;       00100100
;       -------^
;      =00000000
;      00110101
;      00010010
;      -------^
;     =00000000
;     00110101
;     00001001
;     -------^
;     00110101
;    00110101
;    00000100
;    -------^
;   =00000000
;   00110101
;   00000010
;   -------^
;  =00000000
;  00110101
;  00000001
; 00110101

      
.endscope
.endif  ; guard