; int  _DoubleUnsArr(a,n)
 ;
 ; ARGUMENT
 ;      unsigned *a[];
 ;      unsigned n;
 ;
 ; DESCRIPTION
 ;      Doubles the number a (taken as one number of 'n' 16-bit unsigned's).
 ;
 ; SIDE EFFECTS
 ;      Overflow if sign bit goes set in high-order unsigned
 ;
 ; RETURNS
 ;      None, athough they are set in AX for future use if needed
 ;
 ; AUTHOR
 ;  Andy Anderson   31-JAN-1987  14:45
 ;   Copyright (C) 1987-90 Greenleaf Software Inc.  All Rights Reserved.
 ;
 ; MODIFICATIONS
 ;
 ;
 ;
        include model.h
        include prologue.h
        include gm.equ


        pseg    gmath
;
;
;  if large memory model then:
;
;       parm1_ = ptr to source 1
;       parm3_ = number of words to shift left (multipy by 2)
;
;  for if small model then
;       parm1_ = ptr to source1
;       parm2_ = number of words to shift left (multipy by 2)
;
;

        cproc   _DoubleUnsArr,,_dmi
if      _LDATA
        push    ds
        lds     si,parm1_       ; ptr to a
        mov     cx,parm3_       ; get number of words to shift
else
        mov     si,parm1_
        mov     cx,parm2_       ; ditto for small model
endif

        xor     ax,ax           ; clear flags
lp:
        rcl     Word Ptr [si],1         ; word and multipy it by 2
        inc     si              ; and increase the index (offset)
        inc     si              ;  without disturbing the carry
        loop    lp              ;  for next until done

        jc      overf           ;  carry-out is overflow and

        test    [si-2],8000h    ; overflow if high-order set
        jnz     overf
        mov     ax,GM_SUCCESS   ; otherwise no overflow
exit:
if      _LDATA
        pop     ds
endif
        cproce
overf:
        mov     ax,GM_FAILURE
        jmp short exit
        endps
        END