2 icebp - call debug exception handler – AMD Geode LX [email protected] User Manual
Page 647
AMD Geode™ LX Processors Data Book
647
Instruction Set
33234H
Description
The DMINT instruction saves portions of the processors state to the Debug Management Mode (DMM) header, alters the
processors state for DMM, enters DMM, and then calls the DMM mode handler. Below is the format of the DMM header.
Flags Affected
All EFlags are returned to their reset values.
Exceptions
#UD
If current privilege level is not 0, or the DMM_INST_EN = 0 and if the processor is not in SMM and if the pro-
cessor is not in DMM.
Notes
Data address breakpoints on DMM header addresses that occur when executing the DMINT instruction are ignored.
The DMINT instruction clears the V, X, and H bits of the DMM header. DMINT sets the S bit of the DMM header. The
NEXT_IP failed of the DMM header will point to the instruction after the DMINT.
8.3.4.2
ICEBP - Call Debug Exception Handler
Operation
Same as an INT 1 instruction.
Description
The ICEBP instruction generates a call to the Debug exception handler. It’s advantage over the INT 1 instruction is that it is
a single byte opcode.
Flags Affected
The EFlags are pushed to the stack, and may then be modified before the debug exception handler is called. The EFlags
may be restored by the debug exception handler’s IRET.
Notes
Debuggers should not insert ICEBP instruction immediately after an instruction that alters the stack segment (MOV_SS).
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
DR6
-4
DR7
-8
XDR6
-C
XDR7
-10
SS FLAGS
SS SELECTOR
-14
G
B
0
Av
0
1
DPL
1
0
E
W
A
INDEX
TI
RPL
CS FLAGS
CS SELECTOR
-18
G
D
0
Av
0
1
DPL
1
1
C
f
R
A
INDEX
TI
RPL
CS BASE
-1C
0
CS LIMIT
-20
CURRENT_IP
-24
NEXT_IP
-28
CR0
-2C
EFLAGS
-30
0
c
w
0
c
r
0
V
X
0
H
S
0
0
0
-34
TEMP6
-38
AC TEMP0
-3C
Opcode
Instruction
Clocks
Description
F1
ICEBP
29+
Call Debug Exception Handler