Opcode Ex9E not working as expected

[gulrak]

First of all: Thank you for your work on an improved CHIPOS version!

While testing it agains my DREAM6800 emulation, I came across an issue that is resulting from the modifications:

The Ex9E opcode is not working in the current CHIPOSLO version. The Problem originates in the reorganization of the skip opcode handling.

The relevant code:

SKFKEY: JSR     KEYINP      ; INTERROGATE KEYBOARD  <--- This sets the key in KEYCOD and A, A not same as PIR+1 anymore!!!
        TST     BADRED      ; KEY DOWN?
        BEQ     SKFK1
        LDAB    #$A1        ; WHAT INSTRN?
        CMPB    PIR+1       ; SKF VX#KEY   <--- This still works as it doesn't rely on A being content of PIR+1
        BEQ     SKIP2
        RTS                 ; NO KEY GO FETCH
SKFK1:  CMPA    #$9E.       ;  <--- But this now compares the pressed key against $9E, not the second opcode byte
        BEQ     SKFEQ
SKFNE:  CMPA    VX
        BNE     SKIP2
        RTS
LETVK:  ADDA    VX
        BRA     PUTVX
RANDV:  BSR     RANDOM      ; GET RANDOM BYTE
        ANDA    PIR+1
        BRA     PUTVX

The original code in comparison does explicitly use PIR+1:

SKFK1:  LDAB  	#$9E
        CMPB  	PIR+1       ; WHAT INSTRN?
        BEQ     SKFEQ
        BRA     SKFNE

I might try to fix it myself and would put out a PR if I do, but I'm not sure if and when I would manage to do so.