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/*[
enter.c
LOCAL CHAR SccsID[]="@(#)enter.c 1.7 01/19/95";
ENTER 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 <enter.h>
#include <c_page.h>
#include <fault.h>
/*
=====================================================================
EXTERNAL ROUTINES STARTS HERE.
=====================================================================
*/
GLOBAL VOID
ENTER16
IFN2(
IU32, op1, /* immediate data space required */
IU32, op2 /* level (indicates parameters which must be copied) */
)
{
IU32 frame_ptr;
IS32 p_delta = 0; /* posn of parameter relative to BP */
IU32 p_addr; /* memory address of parameter */
IU32 param; /* parameter read via BP */
op2 &= 0x1f; /* take level MOD 32 */
/* check room on stack for new data */
validate_stack_space(USE_SP, (ISM32)op2+1);
/* check old parameters exist */
if ( op2 > 1 )
{
/*
BP is pointing to the old stack before the parameters
were actually pushed, we therefore test for the presence
of the parameters by seeing if they could have been pushed,
if so they exist now.
We have to take care of the READ/WRITE stack addressability
ourselves. Because we have checked the new data can be
written we know the next call can not fail because of access
problems, however we don't yet know if the stack is readable.
Note we have been a bit severe on the paging unit because we
are asking if the old parameters could be written, if so they
can certainly be read from the point of view of the paging
unit!
*/
/* do access check */
if ( GET_SS_AR_R() == 0 )
SF((IU16)0, FAULT_ENTER16_ACCESS);
/* now we know 'frigged' limit check is ok */
validate_stack_space(USE_BP, (ISM32)op2-1);
}
/* all ok - process instruction */
spush((IU32)GET_BP()); /* push BP */
frame_ptr = GetStackPointer(); /* save (E)SP */
if ( op2 > 0 )
{
/* level is >=1, copy stack parameters if they exist */
while ( --op2 > 0 )
{
/* copy parameter */
p_delta -= 2; /* decrement to next parameter */
/* calculate parameter address in 32/16bit arithmetic */
p_addr = get_current_BP() + p_delta;
if ( GET_SS_AR_X() == 0 ) /* look at SS 'B' bit */
p_addr &= WORD_MASK;
p_addr += GET_SS_BASE();
param = (IU32)vir_read_word(p_addr, NO_PHYSICAL_MAPPING);
spush(param);
}
spush((IU32)frame_ptr); /* save old (E)SP */
}
/* update (E)BP */
set_current_BP(frame_ptr);
/* finally allocate immediate data space on stack */
if ( op1 )
byte_change_SP((IS32)-op1);
}
GLOBAL VOID
ENTER32
IFN2(
IU32, op1, /* immediate data space required */
IU32, op2 /* level (indicates parameters which must be copied) */
)
{
IU32 frame_ptr;
IS32 p_delta = 0; /* posn of parameter relative to EBP */
IU32 p_addr; /* memory address of parameter */
IU32 param; /* parameter read via EBP */
op2 &= 0x1f; /* take level MOD 32 */
/* check room on stack for new data */
validate_stack_space(USE_SP, (ISM32)op2+1);
/* check old parameters exist */
if ( op2 > 1 )
{
/*
EBP is pointing to the old stack before the parameters
were actually pushed, we therefore test for the presence
of the parameters by seeing if they could have been pushed,
if so they exist now.
We have to take care of the READ/WRITE stack addressability
ourselves. Because we have checked the new data can be
written we know the next call can not fail because of access
problems, however we don't yet know if the stack is readable.
Note we have been a bit severe on the paging unit because we
are asking if the old parameters could be written, if so they
can certainly be read from the point of view of the paging
unit!
*/
/* do access check */
if ( GET_SS_AR_R() == 0 )
SF((IU16)0, FAULT_ENTER32_ACCESS);
/* now we know 'frigged' limit check is ok */
validate_stack_space(USE_BP, (ISM32)op2-1);
}
/* all ok - process instruction */
spush((IU32)GET_EBP()); /* push EBP */
frame_ptr = GetStackPointer(); /* save (E)SP */
if ( op2 > 0 )
{
/* level is >=1, copy stack parameters if they exist */
while ( --op2 > 0 )
{
/* copy parameter */
p_delta -= 4; /* decrement to next parameter */
/* calculate parameter address in 32/16bit arithmetic */
p_addr = get_current_BP() + p_delta;
if ( GET_SS_AR_X() == 0 ) /* look at SS 'B' bit */
p_addr &= WORD_MASK;
p_addr += GET_SS_BASE();
param = (IU32)vir_read_dword(p_addr, NO_PHYSICAL_MAPPING);
spush(param);
}
spush((IU32)frame_ptr); /* save old (E)SP */
}
/* update (E)BP */
set_current_BP(frame_ptr);
/* finally allocate immediate data space on stack */
if ( op1 )
byte_change_SP((IS32)-op1);
}
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