SDCC and malloc() - allocating much less memory than is available

Posted by Duncan Bayne on Stack Overflow See other posts from Stack Overflow or by Duncan Bayne
Published on 2013-06-27T23:29:35Z Indexed on 2013/07/02 23:06 UTC
Read the original article Hit count: 249

Filed under:

c

|

malloc

|

sdcc

|

retro-computing

|

amstrad

When I run compile this code with SDCC 3.1.0, and run it on an Amstrad CPC 464 (under emulation, with WinCPC 0.9.26 running on Wine):

void _test_malloc()
{
  long idx = 0;
  while (1)
    {
      if (malloc(5))
    {
      printf("%ld\r\n", ++idx);
    }
      else
    {
      printf("done");
      break;
    }
  }
}

... it consistently taps out at 92 malloc()s. I make that 460 bytes, which leads me to a couple of questions:

What is malloc() doing on this system? I was sort of hoping for an order of magnitude more storage even on a 64kB system
The behaviour is consistent on 64kB systems and 128kB systems; do I have to perform some sort of magic to access the additional memory, like manual bank switching?

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SDCC and malloc() - allocating much less memory than is available - Developer IT

SDCC and malloc() - allocating much less memory than is available

c

malloc

sdcc

retro-computing

amstrad

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