Subversion Repositories planix.SVN

Q       = 0
N       = 1
D       = 2
CC      = 3
TMP     = 11

TEXT    save<>(SB), 1, $0
        MOVW    R(Q), 0(FP)
        MOVW    R(N), 4(FP)
        MOVW    R(D), 8(FP)
        MOVW    R(CC), 12(FP)

        MOVW    R(TMP), R(Q)            /* numerator */
        MOVW    20(FP), R(D)            /* denominator */
        CMP     $0, R(D)
        BNE     s1
        MOVW    -1(R(D)), R(TMP)        /* divide by zero fault */
s1:     RET

TEXT    rest<>(SB), 1, $0
        MOVW    0(FP), R(Q)
        MOVW    4(FP), R(N)
        MOVW    8(FP), R(D)
        MOVW    12(FP), R(CC)
/*
 * return to caller
 * of rest<>
 */
        MOVW    0(R13), R14
        ADD     $20, R13
        B       (R14)

TEXT    div<>(SB), 1, $0
        MOVW    $32, R(CC)
/*
 * skip zeros 8-at-a-time
 */
e1:
        AND.S   $(0xff<<24),R(Q), R(N)
        BNE     e2
        SLL     $8, R(Q)
        SUB.S   $8, R(CC)
        BNE     e1
        RET
e2:
        MOVW    $0, R(N)

loop:
/*
 * shift R(N||Q) left one
 */
        SLL     $1, R(N)
        CMP     $0, R(Q)
        ORR.LT  $1, R(N)
        SLL     $1, R(Q)

/*
 * compare numerator to denominator
 * if less, subtract and set quotent bit
 */
        CMP     R(D), R(N)
        ORR.HS  $1, R(Q)
        SUB.HS  R(D), R(N)
        SUB.S   $1, R(CC)
        BNE     loop
        RET

TEXT    _div(SB), 1, $16
        BL      save<>(SB)
        CMP     $0, R(Q)
        BGE     d1
        RSB     $0, R(Q), R(Q)
        CMP     $0, R(D)
        BGE     d2
        RSB     $0, R(D), R(D)
d0:
        BL      div<>(SB)               /* none/both neg */
        MOVW    R(Q), R(TMP)
        B       out
d1:
        CMP     $0, R(D)
        BGE     d0
        RSB     $0, R(D), R(D)
d2:
        BL      div<>(SB)               /* one neg */
        RSB     $0, R(Q), R(TMP)
        B       out

TEXT    _mod(SB), 1, $16
        BL      save<>(SB)
        CMP     $0, R(D)
        RSB.LT  $0, R(D), R(D)
        CMP     $0, R(Q)
        BGE     m1
        RSB     $0, R(Q), R(Q)
        BL      div<>(SB)               /* neg numerator */
        RSB     $0, R(N), R(TMP)
        B       out
m1:
        BL      div<>(SB)               /* pos numerator */
        MOVW    R(N), R(TMP)
        B       out

TEXT    _divu(SB), 1, $16
        BL      save<>(SB)
        BL      div<>(SB)
        MOVW    R(Q), R(TMP)
        B       out

TEXT    _modu(SB), 1, $16
        BL      save<>(SB)
        BL      div<>(SB)
        MOVW    R(N), R(TMP)
        B       out

out:
        BL      rest<>(SB)
        B       out