Intel 80386

COPROCESSOR HARDWARE INTERFACE
8086/87/88/186 MACRO ASSEMBLER
Test for presence of 8 Nunerics Chip, Revision 1.0
PAGE
DOS 3.20 (033·N) 8086/87/88/186 MACRO ASSEMBLER V2.0 ASSEMBLY OF MODULE TEST_NPX
OBJECT MODULE PLACED IN F1NDNPX.OBJ
lOC OBJ
0000 (100
1711
)
DOCS ?111
0000 0000
0000
0000
0000
90DBE3
0003 BEOOOO
0006 C7045A5A
OOOA 90DD3C
0000 803COO
0010 752A
0012 90093C
0015 8B04
0017 253Fl0
001A 3D3FOO
0010 7510
LINE
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SOURCE
Stitle('Test for presence of 8 NlIOOrics Chip, Revision 1.0
1
)
name Test_NPX
stack segment stack 'stack'
dw 100 dup (1)
sst dw
stack ends
dsta segment pub lie 'datal
t_ dw
Oh
data ends
dgroup
group
data, stack
cgroup
group
code
code segment publ ic . code'
assllOO cs:cgroup, ds:dgroup
start:
look for an 8087, 80287, or 80387 NPX.
Note that we camot execute \lAIl on 8086/88 if no 8087 is present.
test npx:
- fninit ; Must use non-wait form
mov si ,offset dgroup:terrp
mav word ptr [si] ,5ASAH ; Initial fze terrp to non-zero vaLue
fnstsw [si] ; Must use non-wait form of fstsw
It is not necessary to use 8 \lAIl instruction
after fnstsw or fnstcw. Do not use one here.
cnp byte ptr [s11 ,0 i See if correct status with zeroes was read
jne
J~ if not a val id status word, meaning no NPX
Now see if ones can be correctly written from the controL word.
fnstcw [sil
mov ax, [sil
and ax,103fh
cap
ax,3fh
jne nOJ'px
; Look at the control word; do not use WAIT form
; Do not use a WAIT instruction herel
See
if ones can be wr i tten by NPX
See if selected parts of control word look. OK
Check. that ones and zeroes were correctly read
J~ if no NPX is installed
Some nunerics chip is installed. NPX instructions and WAIT are now safe.
See if the NPX is an 8087, 80287, or 80387.
This code is necessary if a denonnal exception handler is used or the
new 80387 instructions will be used.
Figure 5-4. Software Routine to Recognize the 80287
5-9
G40107