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[/] [zipcpu/] [trunk/] [sw/] [lib/] [divu.S] - Diff between revs 59 and 69

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Rev 59 Rev 69
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;
;
; Purpose:      Zip assembly file for running doing an unsigned divide.
; Purpose:      Zip assembly file for running doing an unsigned divide.
;               This routine is also called by the signed divide.
;               This routine is also called by the signed divide.
;
;
; Creator:      Dan Gisselquist, Ph.D.
; Creator:      Dan Gisselquist, Ph.D.
;               Gisselquist Tecnology, LLC
;               Gisselquist Technology, LLC
;
;
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;
;
; Copyright (C) 2015, Gisselquist Technology, LLC
; Copyright (C) 2015, Gisselquist Technology, LLC
;
;
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;
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;
;
;
;
divu:   ; Given R0,R1, computer R0 = R0/R1 and R1 = R0%R1
lib_divu:       ; Given R0,R1, computer R0 = R0/R1 and R1 = R0%R1
        TST     -1,R1
        TST     -1,R1
        ; BNZ   divu_valid_divide
        ; BNZ   divu_valid_divide
        CLR.Z   R0              ; Should be a divide by zero error / trap
        CLR.Z   R0              ; Should be a divide by zero error / trap
        RETN.Z
        JMP.Z   R2
divu_valid_divide:
divu_valid_divide:
        SUB     1,SP
        SUB     2,SP
 
        STO     R2,(SP)
        STO     R3,1(SP)
        STO     R3,1(SP)
        ;
        ;
        LDI     1,R2    ; Here's where we record the bit we are working on
        LDI     1,R2    ; Here's where we record the bit we are working on
        CLR     R3      ; Here's where we build our result
        CLR     R3      ; Here's where we build our result
; Our original loop rejoin point, before a touch of unrolling
; Our original loop rejoin point, before a touch of unrolling
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        BNZ     divu_next_loop
        BNZ     divu_next_loop
 
 
divu_record_result:
divu_record_result:
        MOV     R0,R1
        MOV     R0,R1
        MOV     R3,R0
        MOV     R3,R0
 
        LOD     (SP),R2
        LOD     1(SP),R3
        LOD     1(SP),R3
        LOD     2(SP),R2
        ADD     2,SP
        ADD     1,SP
 
        JMP     R2
        JMP     R2
 
 

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