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parisc: avoid undefined shift in cnv_float.h
The attached change fixes a float conversion problem found running the GCC testsuite with GCC configured with --with-arch=2.0. The actual problem occurs for an exponent value of 63. This is the maximum exponent value that can be passed. This causes a left shift by 32 in the else hunk of the macro. This causes undefined behavior and the wrong value is returned for dresultB. The fix is the check "exponent <= 62". If the exponent is 63, dresultB is set to 0. The patch also optimizes the operation a bit by copying "Sall(sgl_value) << SGL_EXP_LENGTH" to val, so that sgl_value is not modified. Signed-off-by: John David Anglin <dave.anglin@bell.net> Signed-off-by: Helge Deller <deller@gmx.de>
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@ -347,16 +347,15 @@
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Sgl_isinexact_to_fix(sgl_value,exponent)
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#define Duint_from_sgl_mantissa(sgl_value,exponent,dresultA,dresultB) \
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{Sall(sgl_value) <<= SGL_EXP_LENGTH; /* left-justify */ \
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{unsigned int val = Sall(sgl_value) << SGL_EXP_LENGTH; \
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if (exponent <= 31) { \
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Dintp1(dresultA) = 0; \
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Dintp2(dresultB) = (unsigned)Sall(sgl_value) >> (31 - exponent); \
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Dintp1(dresultA) = 0; \
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Dintp2(dresultB) = val >> (31 - exponent); \
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} \
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else { \
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Dintp1(dresultA) = Sall(sgl_value) >> (63 - exponent); \
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Dintp2(dresultB) = Sall(sgl_value) << (exponent - 31); \
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Dintp1(dresultA) = val >> (63 - exponent); \
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Dintp2(dresultB) = exponent <= 62 ? val << (exponent - 31) : 0; \
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} \
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Sall(sgl_value) >>= SGL_EXP_LENGTH; /* return to original */ \
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}
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#define Duint_setzero(dresultA,dresultB) \
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