Ch 10: Hardware Interrupts and PIC 8259

Write an 8088 assembly language program to hook and implement a custom Breakpoint Interrupt Service Routine (INT 3 ISR). The program must back up the original interrupt vector, install the new handler, generate a breakpoint trigger, display a notification message, and safely restore the original handler.

int 3

Write the complete 8088 assembly language implementation of a Breakpoint Interrupt Service Routine (INT 3 ISR) for a software debugger. The routine must save processor register state, restore the original instruction opcode, display register values on screen, wait for user keypress input, and resume program execution.

debugISR:
    push bp
    mov bp, sp
    push ax
    push bx
    push cx
    push dx
    push si
    push di
    push ds
    push es

In a software debugger program, how is single-stepping mode enabled using the Trap Flag (TF) on the stack frame during an Interrupt Service Routine (ISR)?

or word [bp+6], 0x0100
iret

Write the 8088 assembly initialization code required by a software debugger to hook the Single-Step Interrupt (INT 1), Breakpoint Interrupt (INT 3), and Keyboard Interrupt (INT 9) vectors in the Interrupt Vector Table (IVT).

xor ax, ax
mov es, ax
mov word [es:1*4], trapisr
mov [es:1*4+2], cs