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88 lines
1.8 KiB
88 lines
1.8 KiB
/*[
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shl.c
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LOCAL CHAR SccsID[]="@(#)shl.c 1.5 02/09/94";
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SHL 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 <shl.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 'shl'. */
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/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
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GLOBAL VOID
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SHL
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IFN3(
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IU32 *, pop1, /* pntr to dst/src operand */
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IU32, op2, /* shift 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 msb;
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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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msb = SZ2MSB(op_sz);
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/*
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==== =================
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|CF| <-- | | | | | | | | | <-- 0
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==== =================
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*/
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result = *pop1 << op2 - 1; /* Do all but last shift */
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SET_CF((result & msb) != 0); /* CF = MSB */
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result = result << 1 & SZ2MASK(op_sz); /* Do final shift */
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SET_PF(pf_table[result & BYTE_MASK]);
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SET_ZF(result == 0);
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SET_SF((result & msb) != 0); /* SF = MSB */
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/* OF = CF ^ SF(MSB) */
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new_of = GET_CF() ^ GET_SF();
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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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/* Set undefined flag(s) */
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#ifdef SET_UNDEFINED_FLAG
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SET_AF(UNDEFINED_FLAG);
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#endif
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*pop1 = result; /* Return answer */
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}
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