machine/8042kbdc.cpp: BeOS 3.x/4.x erratic keyboard

[angelosa]

Steps to reproduce (shortest way):

1. grab a BeOS 3.x x86 floppy disk;
2. mamefoo pcipc -flop1 <pathto>bootdisk.img (HDD/CD doesn't matter)
3. Most often the "Press Space Bar for boot options" doesn't work (necessary for loading from CD), wait until it prompts you to select Boot Options;

None of the keyboard scancodes seems to match what the system expects, this is also repeated in an actual BeOS 4.0 installation, where only mouse works while keyboard gets detected with wrong & stuck keys in Keymap tool.

BeOS 3.1 notes:

1. PC=401eae cmp eax,0h, eax always 1
2. Following snippet for the scancode interpretation (roughly enter/esc/directional arrows as also prompted by the SW):

00413D86: 89 45 E0          mov     [ebp-20h],eax
00413D89: 8B 45 E0          mov     eax,[ebp-20h]
00413D8C: 2D 57 00 00 00    sub     eax,57h
00413D91: 74 3C             je      413DCFh
00413D93: 2D 0B 00 00 00    sub     eax,0Bh
00413D98: 0F 84 85 00 00 00 je      413E23h
00413D9E: 2D C4 FF FF FF    sub     eax,0FFFFFFC4h
00413DA3: 0F 84 CA 00 00 00 je      413E73h
00413DA9: 2D DB FF FF FF    sub     eax,0FFFFFFDBh
00413DAE: 0F 84 31 01 00 00 je      413EE5h
00413DB4: 2D 46 00 00 00    sub     eax,46h
00413DB9: 0F 84 2D 01 00 00 je      413EECh
00413DBF: 2D 14 00 00 00    sub     eax,14h
00413DC4: 0F 84 22 01 00 00 je      413EECh
00413DCA: E9 70 01 00 00    jmp     413F3Fh

[angelosa]

Related to #11797 ?