https://github.com/ucb-bar/berkeley-hardfloat

https://github.com/ucb-bar/berkeley-hardfloat

Last synced: 3 months ago
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• Host: GitHub
• URL: https://github.com/ucb-bar/berkeley-hardfloat
• Owner: ucb-bar
• License: other
• Created: 2014-09-08T04:13:04.000Z (about 10 years ago)
• Default Branch: master
• Last Pushed: 2024-06-05T21:53:34.000Z (5 months ago)
• Last Synced: 2024-07-16T18:58:43.724Z (4 months ago)
• Language: Scala
• Size: 1.29 MB
• Stars: 274
• Watchers: 53
• Forks: 85
• Open Issues: 19
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

• awesome-opensource-hardware - berkeley-hardfloat

README

        
Berkeley Hardware Floating-Point Units

======================================

This repository contains hardware floating-point units written in Chisel.

This library contains parameterized floating-point units for fused multiply-add

operations, conversions between integer and floating-point numbers, and

conversions between floating-point conversions with different precision.

**WARNING**:

These units are works in progress.  They may not be yet completely free of

bugs, nor are they fully optimized.

Recoded Format

--------------

The floating-point units in this repository work on an internal recoded format

(exponent has an additional bit) to handle subnormal numbers more efficiently

in a microprocessor.  A more detailed explanation will come soon, but in the

mean time here are some example mappings for single-precision numbers.

    IEEE format                           Recoded format

    ----------------------------------    -----------------------------------

    s 00000000 00000000000000000000000    s 000------ 00000000000000000000000

    s 00000000 00000000000000000000001    s 001101011 00000000000000000000000

    s 00000000 0000000000000000000001f    s 001101100 f0000000000000000000000

    s 00000000 000000000000000000001ff    s 001101101 ff000000000000000000000

        ...              ...                   ...              ... 

    s 00000000 001ffffffffffffffffffff    s 001111111 ffffffffffffffffffff000

    s 00000000 01fffffffffffffffffffff    s 010000000 fffffffffffffffffffff00

    s 00000000 1ffffffffffffffffffffff    s 010000001 ffffffffffffffffffffff0

    s 00000001 fffffffffffffffffffffff    s 010000010 fffffffffffffffffffffff

    s 00000010 fffffffffffffffffffffff    s 010000011 fffffffffffffffffffffff

        ...              ...                   ...              ... 

    s 11111101 fffffffffffffffffffffff    s 101111110 fffffffffffffffffffffff

    s 11111110 fffffffffffffffffffffff    s 101111111 fffffffffffffffffffffff

    s 11111111 00000000000000000000000    s 110------ -----------------------

    s 11111111 fffffffffffffffffffffff    s 111------ fffffffffffffffffffffff

Unit-Testing

------------

To unit-test these floating-point units, you need the berkeley-testfloat-3

package.

To test floating-point units with the C simulator:

    $ make