home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
Magnum One
/
Magnum One (Mid-American Digital) (Disc Manufacturing).iso
/
d12
/
util307.arc
/
87ERROR.DOC
< prev
next >
Wrap
Text File
|
1987-03-04
|
2KB
|
33 lines
The program 87ERROR.COM is a simple 8087 error interrupt handler for
the IBM Personal Computer. To install the error handler just run 87ERROR.COM
from DOS (ver. 1.1, 2.XX). When an error interrupt is generated by the 8087
a letter in reverse video will appear in the upper right hand corner of the
monochrome display. The letter will indicate the general type of error which
caused the 8087 to generate an interrupt as below in the table:
D --------- Denormalized operand
Z --------- Divide by zero
O --------- Overflow
U --------- Underflow
P --------- Precision error
The interrupt pin on the 8087 is connected with the parity checking
logic on the mother board. Because of this fact the program needs to jump to
the ROM BIOS just in case the NMI (Non Maskable Interrupt) was generated by a
parity error and not by the 8087. The address of the jump at the end of the
interrupt handler "JMP FAR PTR ROMADR" may need to be changed depending on
what version of the IBM ROM BIOS you have.
The correct address can be found at 0H:8H to 0H:0BH for the jump to the
IBM ROM BIOS. The first two memory locations contain the offset and the next
two memory locations contain the segment address. Change the address on the
line "ROM SEGMENT AT 0F000H" to the segment address just found. Then
change the address on the line " ORG 0E2C3H" to the offset address
just found. You can now generate a new 87ERROR.COM file from the new
87ERROR.ASM source file.
Leland C. Scott
18140 Locherbie
Birmingham, Michigan 48009
(313) 642-9783