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author | Andreas Sandberg <andreas@sandberg.pp.se> | 2013-09-30 12:00:20 +0200 |
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committer | Andreas Sandberg <andreas@sandberg.pp.se> | 2013-09-30 12:00:20 +0200 |
commit | 654d1e675a3dc1f598aeadb0824bdb3357820a59 (patch) | |
tree | e249108fcd6737dda985b993c95d926a33abca21 /src/arch/mips/kernel_stats.hh | |
parent | c299dcedc6d73aab56d9c659623d7112c2e9c4bb (diff) | |
download | gem5-654d1e675a3dc1f598aeadb0824bdb3357820a59.tar.xz |
x86: Add support for loading 32-bit and 80-bit floats in the x87
The x87 FPU supports three floating point formats: 32-bit, 64-bit, and
80-bit floats. The current gem5 implementation supports 32-bit and
64-bit floats, but only works correctly for 64-bit floats. This
changeset fixes the 32-bit float handling by correctly loading and
rounding (using truncation) 32-bit floats instead of simply truncating
the bit pattern.
80-bit floats are loaded by first loading the 80-bits of the float to
two temporary integer registers. A micro-op (cvtint_fp80) then
converts the contents of the two integer registers to the internal FP
representation (double). Similarly, when storing an 80-bit float,
there are two conversion routines (ctvfp80h_int and cvtfp80l_int) that
convert an internal FP register to 80-bit and stores the upper 64-bits
or lower 32-bits to an integer register, which is the written to
memory using normal integer stores.
Diffstat (limited to 'src/arch/mips/kernel_stats.hh')
0 files changed, 0 insertions, 0 deletions