OpenEuphoria

RE: Memory Question

• Posted by CoJaBo <cojabo at suscom.net> Feb 15, 2004
• 590 views

I think this will work(I don't think it was tested on exw yet):


en,

I just happen to have some machine code that I wrote (for Neil gfx lib
long ago) that will convert a physical address to an poke-able
Causeway-friendly virtual address. In the code below, replace
PhysBasePtr with your physical address, and the result video_mem will be

the address that you can poke to.

The machine code uses Causeway interrupt #31, function #19,
"Linear2Near" - CONVERT LINEAR TO APP-RELATIVE ADDRESS
(http://www.delorie.com/djgpp/doc/rbinter/ix/31/FF.html)

Regards,
Pete

include machine.e

-- code to convert the physical base address to the linear frame buffer
address
constant getlfb = allocate(86)
poke(getlfb, {
     #60,                    --    0: pusha
     #8B,#1D,#52,#2B,#14,#02,--    1: mov ebx, [@linear]
     #85,#DB,                --    7: test ebx, ebx
     #74,#0C,                --    9: jz batman
     #89,#D9,                --    B: mov ecx, ebx
     #C1,#EB,#10,            --    D: shr ebx, 16
     #B8,#01,#08,#00,#00,    --   10: mov eax, #801
     #CD,#31,                --   15: int #31
                             --   17: batman:
     #BB,#00,#00,#00,#00,    --   17: mov ebx, PhysBasePtr (24)
     #89,#D9,                --   1C: mov ecx, ebx
     #C1,#EB,#10,            --   1E: shr ebx, 16
     #BE,#00,#00,#40,#00,    --   21: mov esi, 4194304
     #89,#F7,                --   26: mov edi, esi
     #C1,#EE,#10,            --   28: shr esi, 16
     #B8,#00,#08,#00,#00,    --   2B: mov eax, #800
     #CD,#31,                --   30: int #31
                             --   32: jc robin
     #C1,#E3,#10,            --   32: shl ebx, 16
     #66,#89,#CB,            --   35: mov bx, cx
     #89,#DE,                --   38: mov esi, ebx
     #B8,#19,#FF,#00,#00,    --   3A: mov eax, #FF19
     #CD,#31,                --   3F: int #31
     #89,#35,#52,#2B,#14,#02,--   41: mov [@linear], esi
     #61,                    --   47: popa
     #C3,                    --   48: ret
                             --   49: robin:
     #31,#C0,                --   49: xor eax, eax
     #A3,#52,#2B,#14,#02,    --   4B: mov [@linear], eax
     #61,                    --   50: popa
     #C3,                    --   51: ret
     #00,#00,#00,#00})       --   52: linear: dd 0 (82)
poke4(getlfb + 3, getlfb + 82) -- @linear
poke4(getlfb + 67, getlfb + 82) -- @linear
poke4(getlfb + 76, getlfb + 82) -- @linear


poke4(getlfb + 24, PhysBasePtr) -- convert physical base address
call(getlfb)                     -- to linear frame buffer
video_mem = peek4u(getlfb + 82)



Daniel Kluss wrote:
> 
> 
> (in dos or win dos box) Does anyone know a good to allocate memory, and 
> get 
> the PHYSICAL address as well as the LOGICAL address, so system hardware 
> can 
> read/write and EUPHORIA can read/write. The only memory space I can find 
> 
> that does that so far is the allocate_low() which the PHY=LOG, but I 
> want to 
> allocate more than 1MB.
> 
>