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authorRichard Henderson <richard.henderson@linaro.org>2018-05-31 14:50:51 +0100
committerPeter Maydell <peter.maydell@linaro.org>2018-05-31 14:50:51 +0100
commit6c2be133a7478e443c99757b833d0f265c48e0a6 (patch)
tree189f5d1d33673312ba739adfa55f866eea2b1092 /include
parent34ffacae085914fce54590ea84bae9c6ad95e2a4 (diff)
tcg: Fix helper function vs host abi for float16
Depending on the host abi, float16, aka uint16_t, values are passed and returned either zero-extended in the host register or with garbage at the top of the host register. The tcg code generator has so far been assuming garbage, as that matches the x86 abi, but this is incorrect for other host abis. Further, target/arm has so far been assuming zero-extended results, so that it may store the 16-bit value into a 32-bit slot with the high 16-bits already clear. Rectify both problems by mapping "f16" in the helper definition to uint32_t instead of (a typedef for) uint16_t. This forces the host compiler to assume garbage in the upper 16 bits on input and to zero-extend the result on output. Cc: qemu-stable@nongnu.org Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Tested-by: Laurent Desnogues <laurent.desnogues@gmail.com> Message-id: 20180522175629.24932-1-richard.henderson@linaro.org Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Diffstat (limited to 'include')
-rw-r--r--include/exec/helper-head.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/include/exec/helper-head.h b/include/exec/helper-head.h
index 15b6a68de3..276dd5afce 100644
--- a/include/exec/helper-head.h
+++ b/include/exec/helper-head.h
@@ -39,7 +39,7 @@
#define dh_ctype_int int
#define dh_ctype_i64 uint64_t
#define dh_ctype_s64 int64_t
-#define dh_ctype_f16 float16
+#define dh_ctype_f16 uint32_t
#define dh_ctype_f32 float32
#define dh_ctype_f64 float64
#define dh_ctype_ptr void *