Fix IAR compiler endianness detection in alignment.h - #838
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Related issue in MbedTLS repo: Mbed-TLS/mbedtls#10381 |
The IAR C/C++ compiler always defines both __LITTLE_ENDIAN__ and __BIG_ENDIAN__ macros internally, assigning '1' to the active endianness and '0' to the inactive one. The previous check defined(__LITTLE_ENDIAN__) always evaluated to true on IAR, causing big-endian targets to be incorrectly treated as little-endian. This commit updates the check to verify the value (__XXXX_ENDIAN__ == 1). Signed-off-by: Linh D. Nguyen <dlinhvn@gmail.com>
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LGTM on code reading.
(I haven't tested because I don't have a big-endian arm testing environment readily available, and I do have access to IAR for arm but the license server is down at the moment.)
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Signed-off-by: Linh D. Nguyen <dlinhvn@gmail.com>
5 tasks
Signed-off-by: Linh D. Nguyen <dlinhvn@gmail.com>
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Description
This PR fixes a critical bug where the IAR compiler always triggers the Little-Endian code path, even when compiling for Big-Endian CPU. Fix Mbed-TLS/mbedtls#10381
The IAR C/C++ compiler always defines both
__LITTLE_ENDIAN__and__BIG_ENDIAN__macros internally, assigning '1' to the active endianness and '0' to the inactive one. The previous checkdefined(__BIG_ENDIAN__)always evaluated to true on IAR. This commit updates the check to verify the actual value:(__BIG_ENDIAN__ == 1).References from IAR Development Guide for several MCU families
[1] ARM: https://wwwfiles.iar.com/arm/webic/doc/EWARM_DevelopmentGuide.ENU.pdf - p.494
[2] Renesas RX: https://wwwfiles.iar.com/RX/webic/doc/EWRX_DevelopmentGuide.ENU.pdf - p. 428
[3] Renesas RL78: https://wwwfiles.iar.com/rl78/EWRL78_DevelopmentGuide.ENU.pdf -p.389
[4] STM8: https://wwwfiles.iar.com/stm8/guides/EWSTM8_DevelopmentGuide.pdf - p.334
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