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/*[
shr.c
LOCAL CHAR SccsID[]="@(#)shr.c 1.5 02/09/94";
SHR CPU functions.
------------------
]*/
#include <insignia.h>
#include <host_def.h>
#include <xt.h>
#include <c_main.h>
#include <c_addr.h>
#include <c_bsic.h>
#include <c_prot.h>
#include <c_seg.h>
#include <c_stack.h>
#include <c_xcptn.h>
#include <c_reg.h>
#include <shr.h>
/*
=====================================================================
EXTERNAL FUNCTIONS START HERE.
=====================================================================
*/
/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
/* Generic - one size fits all 'shr'. */
/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
GLOBAL VOID
SHR
IFN3(
IU32 *, pop1, /* pntr to dst/src operand */
IU32, op2, /* shift count operand */
IUM8, op_sz /* 8, 16 or 32-bit */
)
{
IU32 prelim;
IU32 result;
ISM32 new_of;
/* only use lower five bits of count */
if ( (op2 &= 0x1f) == 0 )
return;
/*
================= ====
0 --> | | | | | | | | | --> |CF|
================= ====
*/
prelim = *pop1 >> op2 - 1; /* Do all but last shift */
SET_CF((prelim & BIT0_MASK) != 0); /* CF = Bit 0 */
/* OF = MSB of operand */
new_of = (prelim & SZ2MSB(op_sz)) != 0;
result = prelim >> 1; /* Do final shift */
SET_PF(pf_table[result & BYTE_MASK]);
SET_ZF(result == 0);
SET_SF(0);
if ( op2 == 1 )
{
SET_OF(new_of);
}
else
{
do_multiple_shiftrot_of(new_of);
}
/* Set undefined flag(s) */
#ifdef SET_UNDEFINED_FLAG
SET_AF(UNDEFINED_FLAG);
#endif
*pop1 = result; /* Return answer */
}
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