/*[
c_div64.c
LOCAL CHAR SccsID[]="@(#)c_div64.c 1.5 02/09/94";
64-bit Divide 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 <c_div64.h>
#include <c_neg64.h>
/*
=====================================================================
EXTERNAL FUNCTIONS START HERE.
=====================================================================
*/
/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
/* Do 64bit = 64bit / 32bit Divide (Signed). */
/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
GLOBAL VOID
div64
IFN4(
IS32 *, hr, /* High 32 bits of dividend/quotient */
IS32 *, lr, /* Low 32 bits of dividend/quotient */
IS32, divisor,
IS32 *, rem /* Remainder */
)
{
if ( *hr & BIT31_MASK )
{
if ( divisor & BIT31_MASK )
{
/* Negative Dividend :: Negative Divisor */
neg64(hr, lr);
divisor = -divisor;
divu64((IU32 *)hr, (IU32 *)lr, (IU32)divisor, (IU32 *)rem);
*rem = -*rem;
}
else
{
/* Negative Dividend :: Positive Divisor */
neg64(hr, lr);
divu64((IU32 *)hr, (IU32 *)lr, (IU32)divisor, (IU32 *)rem);
neg64(hr, lr);
*rem = -*rem;
}
}
else
{
if ( divisor & BIT31_MASK )
{
/* Positive Dividend :: Negative Divisor */
divisor = -divisor;
divu64((IU32 *)hr, (IU32 *)lr, (IU32)divisor, (IU32 *)rem);
neg64(hr, lr);
}
else
{
/* Positive Dividend :: Positive Divisor */
divu64((IU32 *)hr, (IU32 *)lr, (IU32)divisor, (IU32 *)rem);
}
}
}
/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
/* Do 64bit = 64bit / 32bit Divide (Unsigned). */
/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
GLOBAL VOID
divu64
IFN4(
IU32 *, hr, /* High 32 bits of dividend/quotient */
IU32 *, lr, /* Low 32 bits of dividend/quotient */
IU32, divisor,
IU32 *, rem /* Remainder */
)
{
ISM32 count;
IU32 hd; /* High 32 bits of dividend/quotient */
IU32 ld; /* Low 32 bits of dividend/quotient */
IU32 par_div; /* partial dividend */
IU32 carry1;
IU32 carry2;
IU32 carry3;
hd = *hr; /* Get local copies */
ld = *lr;
count = 64; /* Initialise */
par_div = 0;
while ( count != 0 )
{
/* shift <par_div:dividend> left.
We have to watch out for carries from
ld<bit31> to hd<bit0> (carry1) and
hd<bit31> to par_div<bit0> (carry2) and
par_div<bit31> to 'carry' (carry3).
*/
carry1 = carry2 = carry3 = 0;
if ( ld & BIT31_MASK )
carry1 = 1;
if ( hd & BIT31_MASK )
carry2 = 1;
if ( par_div & BIT31_MASK )
carry3 = 1;
ld = ld << 1;
hd = hd << 1 | carry1;
par_div = par_div << 1 | carry2;
/* check if divisor 'goes into' partial dividend */
if ( carry3 || divisor <= par_div )
{
/* Yes it does */
par_div = par_div - divisor;
ld = ld | 1; /* output a 1 bit */
}
count--;
}
*rem = par_div; /* Return results */
*hr = hd;
*lr = ld;
}
