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Revision as of 01:47, 21 January 2004 by 131.155.228.94 (talk)

Things FPC 1.9.x currently doesn't support

New in 1.9.x (not yet in the docs)

  • {$fputype xxx) to select a certain fpu style or -Cfxxx on command line/cfg file
    • all: soft (not yet implemented)
    • i386: x87, sse, sse2
      • code compiled with sse uses the sse to do calculations with the single data type. This code runs only on Pentium III and above and AthlonXP and above
      • code compiled with sse uses the sse unit to do calculations with the single and double data type. This code runs only on PentiumIV and above and Athlon64 and above
    • x86-64: sse64
    • powerpc: standard
    • arm: libgcc, fpa, fpa10, fpa11, vfp
    • procedural property support (property outside a class with normal

SSE Usage

To determine the supported instruction set, use the is_sse_cpu and is_sse2_cpu of the mmx unit. Because the sse code is usually faster than x87-fpu code, it's recommended to use these switches for heavy floating point calculations. If you want an application which runs on all fpu architectures, a possible solution is to put the code into an include file and include this file twice into your program: once compiled with e.g. -Cfsse2 and once without. Use the e.g. is_sse2_cpu variable to select the appropriate code:

 {$fputype x87}
 procedure calc_x87;
 {$i mymathcode.inc}
 {$fputype sse2}
 procedure calc_sse2;
 {$i mymathcode.inc}
 begin 
   if is_sse2_cpu then
     calc_sse2
   else
     calc_x87;
 end;