[HN Gopher] Show HN: I486SX_soft_FPU - Software FPU Emulator for...
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       Show HN: I486SX_soft_FPU - Software FPU Emulator for NetBSD 10 on
       486SX
        
       First Release is Here!  I'm excited to announce the first release
       of i486SX_soft_FPU -- a software FPU emulator for the classic Intel
       486SX CPU, running on NetBSD 10!  This project brings floating-
       point support back to life for 486SX machines, even though modern
       NetBSD versions no longer natively support processors without a
       hardware FPU. If you're into retrocomputing, operating system
       hacking, or just love old-school hardware, check it out!  Project
       page: https://github.com/mezantrop/i486SX_soft_FPU Contributions,
       feedback, and testing are all very welcome!  Let's keep these
       vintage machines alive!  #retrocomputing #NetBSD #486SX #opensource
        
       Author : mezantrop
       Score  : 26 points
       Date   : 2025-04-27 21:04 UTC (1 hours ago)
        
 (HTM) web link (github.com)
 (TXT) w3m dump (github.com)
        
       | dlachausse wrote:
       | These used to be very common before Pentium processors. Many
       | (most?) compiler tool chains included a software FPU emulator.
       | 
       | Very cool project!
        
         | actionfromafar wrote:
         | I think GCC didn't have the emulating library, but the
         | operating system had. (Such as Debian.) So you could compile
         | and link your programs against a soft-float library. (
         | Something like this https://github.com/ant6n/ieeelib )
         | 
         | What this NetBSD project does is not exactly like that though,
         | it lets programs use regular 487 float instructions, which are
         | trapped by the kernel, which steps in and emulates what the
         | hardware float instruction would have done.
         | 
         | It worked very well for regular program, because most programs
         | would not use float instructions to any significant degree.
         | 
         | If you however were going to use floats a lot for long
         | calculations, a soft-float library would be much faster.
        
       | rzzzt wrote:
       | That .jpg in the readme file loaded from right to left. What is
       | this sorcery?
        
         | actionfromafar wrote:
         | Apparently1 :                   <img align="right">
         | 
         | I'm also impressed. :-D
         | 
         | 1:
         | https://github.com/mezantrop/i486SX_soft_FPU/blob/main/READM...
        
         | adzm wrote:
         | Pretty sure it's orientation in the jpeg itself
        
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       (page generated 2025-04-27 23:00 UTC)