Bits 5..0 (rrrrrr) define the ROM page to show.
Brunword pages 1,2,3 appear in ROM select positions 1,2,3 only. They are repeated every 64respectively. No other pages of the Brunword ROM can be selected in shown using this waymethod.They are repeated every 64 "ROM" slots.
The upper ROM enable/disable mechanism works with them, and so does the write through to RAM. They operate just like standard CPC Roms.
The following applies:
x11bbb0ppx11bbbepp
bbb define the 64K Bank. pp define the 16K page within that bank.
bit 7 is ignored.
Bit 6 and 5 must be 1. Bit 2 must be is 0to make the ROM page visible in the range &4000-&7fff.Bit 2 is 1 to disable the ROM page in the range &4000-&7fff. All pages of the Brunword ROM can be selected this way. The upper ROM enable/disable mechanism doesn't work, it makes no difference to the visibility of the ROM data here. The ROM visibility is only controlled with bit 2 of the data. RAM write through works. The values repeat every 128. The pages can appear in both &c000-&ffff and &4000-&ffff. Examples: Enable page 1 of the Brunword ROM in the range &4000-&7fff. ld bc,&df00+%01100001 out (c),c Disable Brunword ROM in the range &4000-&7fff. (Bits 4,3 and 1,0 are ignored) ld bc,&df00+%01100100 out (c),c Enable page 1 of the Brunword ROM in the range &c000-&ffff; call kl_u_rom_enable
All pages of the Brunword ROM can be selected this way including 1 ld bc,2,3. The upper ROM enable/disable mechanism doesn't work, so the ROM data appears in the range &4000-&7fff until another ROM selection is made. I df01 out (Arnoldemuc) can't yet determine if the RAM write through works either. The page is always visible in the range &4000-&7fff.,c
The values repeat every 128. If bit 6,5 and 2 are not defined as above then no page is selected, the Disable Brunword ROM page is not visible and it works just like normal RAM. in the range &c000-&ffff:
The pages don't appear in both &c000-&ffff and &4000-&ffff due to the way the data is decoded. The pages appear either at &c000-&ffff OR &4000-&7fff.When I tested, I didn't see the pages appearing in the same location in both. call kl_u_rom_disable
'''MK4'''