Subversion Repositories mips_16

;multiply R3=R1*R2 using add and shift instructions
;       R1: number 1
;       R2: number 2
;       R3: ACC
;       R4: masked R2
;       R5: 16
;       R6: mask, {15'b0,1'b1}
;       R7: conuter

        ADDI    R1,R0,28
        ADDI    R2,R0,17
        ADDI    R6,R0,1
        ADDI    R7,R0,0
        ADDI    R5,R0,16        ;R5=16
L1:     ADDI    R7,R7,1         ;R7++
        AND             R4,R6,R2
        BZ              R4,L2           ;dont need add, skip
        NOP
        ADD             R3,R3,R1        ;accumulate
L2:     SL              R1,R1,R6        ;R1=R1<<1
        SRU             R2,R2,R6        ;R2=R2>>1
        SUB             R4,R5,R7        ;R4=R5-R7
        BZ              R4,L3           ;shift over, go to stop
        NOP
        BZ              R0,L1           ;continue
        NOP
L3:     BZ              R0,L3           ;stop here
        NOP