#include once <neg32.asm>
#include once <_mul32.asm>

    push namespace core

__MULF16:		;
    ld      a, d            ; load sgn into a
    ex      af, af'         ; saves it
    call    __ABS32         ; convert to positive

    exx
    pop hl ; Return address
    pop de ; Low part
    ex (sp), hl ; CALLEE caller convention; Now HL = Hight part, (SP) = Return address
    ex de, hl	; D'E' = High part (B),  H'L' = Low part (B) (must be in DE)

    ex      af, af'
    xor     d               ; A register contains resulting sgn
    ex      af, af'
    call    __ABS32         ; convert to positive

    call __MUL32_64START

; rounding (was not included in zx81)
__ROUND_FIX:					; rounds a 64bit (32.32) fixed point number to 16.16
    ; result returned in dehl
    ; input in h'l'hlb'c'ac
    sla     a               ; result bit 47 to carry
    exx
    ld      hl,0            ; ld does not change carry
    adc     hl,bc           ; hl = hl + 0 + carry
    push	hl

    exx
    ld      bc,0
    adc     hl,bc           ; hl = hl + 0 + carry
    ex		de, hl
    pop		hl              ; rounded result in de.hl

    ex      af, af'         ; recovers result sign
    or      a
    jp      m, __NEG32      ; if negative, negates it

    ret

    pop namespace

