square root

Square root routine

This is a faster square root routine than the one that was previously here, test results say that it’s 26% faster. It is written by Ricardo Bittencourt, so many thanks to him :).

;
;Square root of 16-bit value
;In:  HL = value
;Out:  D = result (rounded down)
;
Sqr16:    ld de,#0040
    ld a,l
    ld l,h
    ld h,d
    or a
    ld b,8
Sqr16_Loop:
    sbc hl,de
    jr nc,Sqr16_Skip
    add hl,de
Sqr16_Skip:
    ccf
    rl d
    add a,a
    adc hl,hl
    add a,a
    adc hl,hl
    djnz Sqr16_Loop
    ret