0x86 Expansion Bus Decoding Enables (0x89 is MSB) (soft reset if bit 31 = 0, hard reset if bit 31 = 1 : all 1) (0x86)

0x86 ( 134 ) Expansion Bus Decoding Enables (0x89 is MSB) (soft reset if bit 31 = 0, hard reset if bit 31 = 1 : all 1) (0x86)

Bits	Description
0	port ff
1	port 7ffd
2	port dffd
3	port 1ffd
4	+3 floating bus
5	port 6b zxn dma
6	port 1f kempston / md1
7	port 37 kempston 2 / md2

Notes:

  The internal port decoding enables always apply.
  When the expansion bus is on, the expansion port decoding enables are logically ANDed with the internal enables.
  A zero bit indicates the internal device is disabled.  If the expansion bus is on, this allows io cycles for
  disabled ports to propagate to the expansion bus, otherwise corresponding io cycles to the expansion bus are filtered.