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Linux on NCD/HMX

Network Computing Device's HMX model X-terminals use a R4600 processor. Linux has not been ported. However there is a Linux on Explora project. The Explora model X-terms use a PowerPC processors. However the systems are very similar.

If you want to port Linux to the HMX, the following information will be useful :

The boot image is checksummed. To get past the CRC check, you must poke 0x20 at offset 0x1000f in Xncdhmx. For more details, see the PPC boot code in the Explora project.

The terminal will gently run any ELF executable, provided it's physical loading address is 0, virtual address is 0x40020000, and it has a header like this :

start:          b       .continue
                dc.w    $20             ; this value is important !
                dc.b    "XncdHMX", 0
                dc.w    0
                dc.w    0
                dc.w    .return, 0

.return:        jr      r31

.continue:      nop

The video RAM is roughly at 0xa0003000 (8 bpp, black is 0xff, white is 0x00). The ROM is at 0xfc000000.