DS>Bonjour All !
DS>    Can someone help me understand how works the CPU generated interrupts
DS>06 & 07 (INVALID OPCODE & NO PROCESSOR EXTENSION AVAILIBLE), I heard that
DS>it is possible to emulate other instructions/processor using those
DS>interrupts, for example, when reprogramming int 06, it is possible, for
DS>example, to emulate pentium instructions on a 486, or even MMX 
nstructions
DS>on a pentium processor. The int 07 can be used to emulate a math
DS>coprocessor when it is not present...
Yes...  my "PC Interrupts" book agrees with that...  The trick to doing such
interrupts is:
1. save all used registers, except those that are SUPPOSED to be changed by
the instruction.
2. use the address on the stack for reading the instruction, something like
this:
******
; start of interrupt
        PUSH    BP
        MOV     BP, SP
        PUSH    DS
        PUSH    BX
        LDS     BX, [BP+02]
; then do some compares or an address table to interpret and execute the
; instruction
; ...
; end the interrupt
        POP     BX
        POP     DS
        POP     BP
        IRET
******
((Cloud))
MauveCloud@juno.com
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