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Update setBit due to overflow in bit shift #623

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Merged
TysonRayJones merged 3 commits into from
May 23, 2025
Merged

Update setBit due to overflow in bit shift #623

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883c58d
Update setBit due to overflow in bit shift
JPRichings May 23, 2025
a0af4ab
updated fix to retain setBit functions signature
JPRichings May 23, 2025
2228568
added James to authorlist
TysonRayJones May 23, 2025
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2 changes: 2 additions & 0 deletions AUTHORS.txt
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Expand Up @@ -44,6 +44,8 @@ Dr Ian Bush [consultant]
HPC

External contributors:
James Richings
patched overflow in bitwise.hpp logic
Luc Jaulmes
patched v4's install process using CMake
Jakub Adamski
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1 change: 1 addition & 0 deletions README.md
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Expand Up @@ -257,6 +257,7 @@ See the [docs](docs/README.md) for enabling acceleration and running the unit te

In addition to QuEST's [authors](AUTHORS.txt), we sincerely thank the following external contributors to QuEST.

- [James Richings](https://github.com/JPRichings) for patching a v4 overflow bug.
- [Luc Jaulmes](https://github.com/lucjaulmes) for patching v4's CMake installation.
- [Jakub Adamski](https://github.com/jjacobx) for optimising distributed communication of max-size messages.
- [Bruno Villasenor Alvarez](https://github.com/bvillasen) of [AMD](https://www.amd.com/en.html) for porting the v3 GPU backend to [HIP](https://github.com/ROCm-Developer-Tools/HIP), for compatibility with AMD GPUs.
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4 changes: 3 additions & 1 deletion quest/src/core/bitwise.hpp
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Expand Up @@ -4,6 +4,7 @@
*
* @author Tyson Jones
* @author Erich Essmann (improved OS agnosticism)
* @author James Richings (patched setBit)
*/

#ifndef BITWISE_HPP
Expand Down Expand Up @@ -106,7 +107,8 @@ INLINE qindex insertBit(qindex number, int bitIndex, int bitValue) {

INLINE qindex setBit(qindex number, int bitIndex, int bitValue) {

qindex bitInPlace = bitValue << bitIndex;
// beware that shifting the raw int would overflow (#623)
qindex bitInPlace = ((qindex) bitValue) << bitIndex;
qindex oneInPlace = QINDEX_ONE << bitIndex;
return (number & ~oneInPlace) | bitInPlace;
}
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