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/*[
jmp.c
LOCAL CHAR SccsID[]="@(#)jmp.c 1.10 01/19/95";
JMP 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 <jmp.h>
#include <c_xfer.h>
#include <c_tsksw.h>
#include <fault.h>
#define TAKE_PROT_MODE_LIMIT_FAULT
/*
=====================================================================
EXTERNAL ROUTINES STARTS HERE.
=====================================================================
*/
/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
/* Process far jmps. */
/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
GLOBAL VOID
JMPF
#ifdef ANSI
(
IU32 op1[2] /* offset:segment pointer */
)
#else
(op1)
IU32 op1[2];
#endif
{
IU16 new_cs; /* The destination */
IU32 new_ip;
IU32 descr_addr; /* cs descriptor address and entry */
CPU_DESCR entry;
ISM32 dest_type; /* category for destination */
IU8 count; /* dummy for call gate count */
new_cs = op1[1];
new_ip = op1[0];
if ( GET_PE() == 0 || GET_VM() == 1 )
{
/* Real Mode or V86 Mode */
#ifdef TAKE_REAL_MODE_LIMIT_FAULT
/*
Although the 386 book says a 16-bit operand should be AND'ed
with 0x0000ffff, a 16-bit operand is never fetched with the
top bits dirty anyway, so we don't AND here.
*/
if ( new_ip > GET_CS_LIMIT() )
GP((IU16)0, FAULT_JMPF_RM_CS_LIMIT);
#else /* TAKE_REAL_MODE_LIMIT_FAULT */
/* The Soft486 EDL CPU does not take Real Mode limit failures.
* Since the Ccpu486 is used as a "reference" cpu we wish it
* to behave a C version of the EDL Cpu rather than as a C
* version of a i486.
*/
#endif /* TAKE_REAL_MODE_LIMIT_FAULT */
load_CS_cache(new_cs, (IU32)0, (CPU_DESCR *)0);
SET_EIP(new_ip);
}
else
{
/* Protected Mode */
/* decode and check final destination */
validate_far_dest(&new_cs, &new_ip, &descr_addr, &count,
&dest_type, JMP_ID);
/* action possible types of target */
switch ( dest_type )
{
case NEW_TASK:
switch_tasks(NOT_RETURNING, NOT_NESTING, new_cs, descr_addr, GET_EIP());
/* limit check new IP (now in new task) */
if ( GET_EIP() > GET_CS_LIMIT() )
GP((IU16)0, FAULT_JMPF_TASK_CS_LIMIT);
break;
case SAME_LEVEL:
read_descriptor_linear(descr_addr, &entry);
/* do limit checking */
if ( new_ip > entry.limit )
GP((IU16)0, FAULT_JMPF_PM_CS_LIMIT);
/* stamp new selector with CPL */
SET_SELECTOR_RPL(new_cs, GET_CPL());
load_CS_cache(new_cs, descr_addr, &entry);
SET_EIP(new_ip);
break;
}
}
}
/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
/* jump near indirect */
/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
GLOBAL VOID
JMPN
IFN1(
IU32, offset
)
{
/*
Although the 386 book says a 16-bit operand should be AND'ed
with 0x0000ffff, a 16-bit operand is never fetched with the
top bits dirty anyway, so we don't AND here.
*/
/* do ip limit check */
#ifdef TAKE_REAL_MODE_LIMIT_FAULT
if ( offset > GET_CS_LIMIT() )
GP((IU16)0, FAULT_JMPN_RM_CS_LIMIT);
#else /* TAKE_REAL_MODE_LIMIT_FAULT */
/* The Soft486 EDL CPU does not take Real Mode limit failures.
* Since the Ccpu486 is used as a "reference" cpu we wish it
* to behave a C version of the EDL Cpu rather than as a C
* version of a i486.
*/
#ifdef TAKE_PROT_MODE_LIMIT_FAULT
if ( GET_PE() == 1 && GET_VM() == 0 )
{
if ( offset > GET_CS_LIMIT() )
GP((IU16)0, FAULT_JMPN_PM_CS_LIMIT);
}
#endif /* TAKE_PROT_MODE_LIMIT_FAULT */
/* The Soft486 EDL CPU does not take Protected Mode limit failues
* for the instructions with relative offsets, Jxx, LOOPxx, JCXZ,
* JMP rel and CALL rel, or instructions with near offsets,
* JMP near and CALL near.
* Since the Ccpu486 is used as a "reference" cpu we wish it
* to behave a C version of the EDL Cpu rather than as a C
* version of a i486.
*/
#endif /* TAKE_REAL_MODE_LIMIT_FAULT */
SET_EIP(offset);
}
/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
/* jump near relative */
/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
GLOBAL VOID
JMPR
IFN1(
IU32, rel_offset
)
{
update_relative_ip(rel_offset);
}
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