1. Re: buffer to assember
Eduardo Uemura Okada wrote:
>
> How can I have a buffer to use in a piece of asm code?
>
> like
> atom buffer
> buffer=allocate(100)
> How can I pass the value of buffer to an asm routine ?
>
> Eduardo Uemura Okada
> e-mail: du at genius.com.br
> homepage: http://www.geocities.com/TimesSquare/Labyrinth/8480
Here's how I would do it with my asm compiler (available on the recent
contributions page or my web page)
; fpixel2.asm
; mov a sequence of pixels via memory buffer to the screen in mode 19
pusha
push ds
pop es
mov ebx, dword x
mov edx, dword y
mov ecx, dword count
mov esi, dword buffer
lea edx, [edx + edx*4]
lea edx, [edx*8 + #14000]
lea edi, [ebx + edx*8]
; ^ that means: edi = ((edx + edx*4)*8 + #14000)*8 + ebx
cld
rep movsb
; move ecx bytes from [ds:esi] to [es:edi]
popa
ret
; end fpixel2.asm
Compiling this with asm.ex gives:
-- fpixel2.inc
include machine.e
code =
{#60, -- 0: pusha
#1E, -- 1: push ds
#07, -- 2: pop es
#BB,#00,#00,#00,#00, -- 3: mov ebx, dword x (4)
#BA,#00,#00,#00,#00, -- 8: mov edx, dword y (9)
#B9,#00,#00,#00,#00, -- D: mov ecx, dword count (14)
#BE,#00,#00,#00,#00, -- 12: mov esi, dword buffer (19)
#8D,#14,#92, -- 17: lea edx, [edx + edx*4]
#8D,#14,#D5,#00,#40,#01,#00,-- 1A: lea edx, [edx*8 + #14000]
#8D,#3C,#D3, -- 21: lea edi, [ebx + edx*8]
#FC, -- 24: cld
#F3,#A4, -- 25: rep movsb
#61, -- 27: popa
#C3} -- 28: ret
global constant fpixel2 = allocate(41)
poke(fpixel2, code)
-- my stuff inserted here
atom x, y, count, buffer
x = 10
y = 20
count = 100
buffer = allocate(count)
mem_set(buffer, 15, count) -- 100 white pixels
include graphics.e
atom junk
junk = graphics_mode(19)
-- end my stuff
poke4(fpixel2 + 4, x)
poke4(fpixel2 + 9, y)
poke4(fpixel2 + 14, count)
poke4(fpixel2 + 19, buffer)
call(fpixel2)
-- end fpixel2
You basically pass the address of a memory buffer the same way as any
other 32-bit integer. But in the asm code you must remember to use that
value as a pointer.
I hope this helps explain things.
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