Skip to content

FPGA: Set fp model to "precise" for ac_fixed sample #1483

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
yuguen merged 2 commits into from
Mar 27, 2023
Merged

FPGA: Set fp model to "precise" for ac_fixed sample #1483

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
b77f77b
set fp-model to precise for emu only
wangdi4 Mar 13, 2023
f61d32e
set fp-model to precise for all platforms
wangdi4 Mar 23, 2023
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
2 changes: 2 additions & 0 deletions DirectProgramming/C++SYCL_FPGA/Tutorials/Features/ac_fixed/README.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -132,6 +132,8 @@ When you use the `ac_fixed` library, keep the following points in mind:

The host program for this tutorial shows the accuracy differences between the result provided by floating point math library and the result provided by the `ac_fixed` math library functions, where the `float` version generates a more accurate result than the smaller-sized `ac_fixed` version.

Note: the program is compiled with fp-model set to "precise", so the accuracy of the floating-point math functions conform to the IEEE standard.

- Emulation vs FPGA Hardware for fixed point math operations

Due to the differences in the internal math implementations, the results from `ac_fixed` math functions in emulation and FPGA hardware might not always be bit-accurate. This tutorial shows how to build and run the sample for emulation and FPGA hardware so you can observe the difference.
Expand Down
4 changes: 2 additions & 2 deletions DirectProgramming/C++SYCL_FPGA/Tutorials/Features/ac_fixed/src/CMakeLists.txt
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -19,9 +19,9 @@ endif()
# 2. /Qactypes Include ac_types headers and link against ac_types emulation libraries
if(WIN32)
set(WIN_FLAG "/EHsc")
set(AC_TYPES_FLAG "/Qactypes")
set(AC_TYPES_FLAG "/Qactypes /fp:precise")
else()
set(AC_TYPES_FLAG "-qactypes")
set(AC_TYPES_FLAG "-qactypes -fp-model=precise")
endif()

# A SYCL ahead-of-time (AoT) compile processes the device code in two stages.
Expand Down