IBM 6278, 6288 Software compatibility, Software interrupts, Machine-sensitive programs, machin

Chapter 6. System compatibility

Software compatibility

To maintain software compatibility, the interrupt polling mechanism that is used by IBM P products is retained. Software that interfaces with the reset port for the IBM Pers positive-edge interrupt sharing (hex oraddress06Fx, where02Fx is the interrupt level) does not creat interference.

Software interrupts

With the

advent

of

software interrupt sharing, software interrupt routines must daisy

routine must check the function value, and

if

it is

not in

the range of function calls

transfer

control

to

the next routine in the chain. Because

software

interrupts

are ini

address

0:0

before

daisy chaining,

check

for

this

case.

If

the

next routine

is

poin

the

function

call

is

out of range,

the appropriate

action

is

to

set

the carry

flag

an

error

condition.

Machine-sensitive programs

Programs		can select machine specific features, but they must			first identify the	machi
IBM	has	defined methods for uniquely	determining	the specific	machine type. The	machin
can	be	found through Interrupt 15H,	Return System	Configuration	Parameters function	(AH)=C0

24 Technical Information Manual