about util/vgabios

[ron minnich]

On Sun, 7 Sep 2003, elife elife wrote:

> 
> Hi,
>   I am trying util/vgabios but encounter a strange problem: testbios seems 
> fetching wrong instruction
> 
> [root at linux vgabios]# ./testbios -s 64k -t ~/lb/500video.bios.bin
> running file /root/lb/500video.bios.bin
> No base specified. defaulting to 0xc0000
> No initial code segment specified. defaulting to 0xc000
> No initial instruction pointer specified. defaulting to 0x0003
> Switching to single step mode.
>         AX=00ff  BX=0000  CX=0000  DX=0080  SP=fff8  BP=0000  SI=0000  
> DI=0000
>         DS=0040  ES=0000  SS=0030  CS=c000  IP=0005   NV UP DI PL NZ NA PO 
> NC
> c000:0003 eb53                JMP       58
> c000:3 -
>         AX=00ff  BX=0000  CX=0000  DX=0080  SP=fff8  BP=0000  SI=0000  
> DI=0000
>         DS=0040  ES=0000  SS=0030  CS=c000  IP=005a   NV UP DI PL NZ NA PO 
> NC
> c000:0058 0000                ADD       [BX+SI],AL
> c000:58 -
> 
> [root at linux lb]# od -x 500vi* |more
> 0000000 aa55 eb60 3753 3034 3030 c237 2a8a 522a
> 0000020 5345 5245 4556 2044 00b1 4f46 2052 4249
> 0000040 204d 4f43 504d 5441 4249 4c49 5449 2a59
> 0000060 2a2a a807 0000 1090 3130 302f 2f37 3032
> 0000100 3230 0000 2e31 3431 3c20 4144 203e 2020
> 0000120 3156 2033 2020 2020 83e9 075e 6f43 7970
> 
> testbios said c000:0058 is 0000 but in file, it's E9835E        JMP     
> 5EDE
> 
> Best Regards!

interesting, I have seen a similar sort of problem but was not sure what 
it was. I'll try to take a look.

ron