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91 lines
1.7 KiB
91 lines
1.7 KiB
/*[
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rcl.c
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LOCAL CHAR SccsID[]="@(#)rcl.c 1.5 02/09/94";
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RCL CPU functions.
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------------------
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]*/
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#include <insignia.h>
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#include <host_def.h>
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#include <xt.h>
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#include <c_main.h>
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#include <c_addr.h>
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#include <c_bsic.h>
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#include <c_prot.h>
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#include <c_seg.h>
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#include <c_stack.h>
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#include <c_xcptn.h>
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#include <c_reg.h>
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#include <rcl.h>
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/*
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=====================================================================
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EXTERNAL FUNCTIONS START HERE.
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=====================================================================
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*/
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/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
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/* Generic - one size fits all 'rcl'. */
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/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
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GLOBAL VOID
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RCL
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IFN3(
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IU32 *, pop1, /* pntr to dst/src operand */
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IU32, op2, /* rotation count operand */
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IUM8, op_sz /* 8, 16 or 32-bit */
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)
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{
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IU32 result;
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IU32 feedback; /* Bit posn to feed into carry */
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ISM32 i;
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ISM32 new_of;
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/* only use lower five bits of count */
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if ( (op2 &= 0x1f) == 0 )
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return;
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/*
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==== =================
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-- |CF| <-- | | | | | | | | | <--
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| ==== ================= |
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---------------------------------
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*/
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feedback = SZ2MSB(op_sz);
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for ( result = *pop1, i = 0; i < op2; i++ )
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{
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if ( result & feedback )
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{
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result = result << 1 | GET_CF();
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SET_CF(1);
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}
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else
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{
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result = result << 1 | GET_CF();
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SET_CF(0);
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}
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}
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/* OF = CF ^ MSB of result */
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new_of = GET_CF() ^ (result & feedback) != 0;
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if ( op2 == 1 )
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{
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SET_OF(new_of);
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}
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else
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{
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do_multiple_shiftrot_of(new_of);
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}
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*pop1 = result; /* Return answer */
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}
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