Message-ID: <39103287.92B19ACF@htsol.com>
Date: Wed, 03 May 2000 17:07:04 +0300
From: Yoram Hofman <yoram AT htsol DOT com>
Organization: Hi-Tech Solutions
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Subject: Assembly code doesn't work properly. 
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Assembly code doesn't work properly.
I need to transfer an image from frame memory controller (far physical
address - "src" in my program) to DRAM.
To optimize the transfer I wrote simple assembly code (my first)
The problem is that it works well in little application. But when I put
this module (.c file as is) to our project it stops to work.

int Read_image_directly(unsigned long src, unsigned char * dest)
{
 unsigned long dest_index = 0;
 unsigned long src_index  = src;
 src_index += IMAGE_START;
 src_index += 1L;

 _farsetsel(mem_sel);

/*      this is original code I want to optimize
 while( dest_index < IMAGE_SIZE )  //IMAGE_SIZE = 154560 bytes
 {
  *(dest + dest_index) = _farnspeekb( src_index );
  dest_index++;
  src_index = src_index + 4;
 }
*/

/* my assembly */
 asm("m_loop:
            cmpl $154559, -4(%ebp)
            jle m_code
            jmp m_end
          m_code:
            movl 12(%ebp),%eax
            movl -4(%ebp),%edx
            addl %edx,%eax
            movl -8(%ebp),%edx
            .byte 0x64
            movb (%edx),%cl
            movb %cl,(%eax)
            incl -4(%ebp)
            incl -8(%ebp)
            incl -8(%ebp)
            incl -8(%ebp)
            incl -8(%ebp)
            jmp m_loop
          m_end:");

 return 1;
}
What's the problem?
One more question for what ".byte 0x64" do I need? (It doesn't work at
all without it)
Lev Nikulin

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