Subversion Repositories SvarDOS

; get the segment to the original process PSP and save it on stack

; Get the segment to the original process PSP. Using int 21h,ah=62h should be

; using int 21h,ah=62h should be safe, RBIL says: "This function does not use

; safe, RBIL says: "This function does not use any of the DOS-internal stacks

; any of the DOS-internal stacks and may thus be called at any time, even

; and may thus be called at any time, even during another INT 21h call"

int 0x21

int 0x21        ; segment of the original PSP is in BX now

; set DS to original PSP

; set DS to the original PSP

pop ds

mov ds, dx

mov dx, [0x18]   ; original stdin and stdout (from the JFT)

mov dx, [bx]   ; original stdin and stdout (from the JFT)

mov dl, [0x1a]   ; the process stderr (3rd entry of the JFT in original PSP)

mov dl, [bx+2]   ; the process stderr (3rd entry of the JFT in original PSP)

mov [0x18], dx

mov [bx], dx

; restore original stdin/stdout handlers in the original PSP

; restore original stdin/stdout handlers in the original JFT

pop dx    ; original process' stdin and stdout handlers (dh=stdin / dl=stdout)

pop dx     ; original process' stdin and stdout handlers

pop bx    ; original process' PSP

pop bx     ; original process' JFT offset

pop ds    ; set DS to the original process so I can access its PSP

pop ds     ; original process' JFT segment

mov [0x18], dx

mov [bx], dx

; restore registers and quit the handler

; restore registers to their original values and quit the handler (AL is