From 198f70589e3c0f0f50da646152443787e959228f Mon Sep 17 00:00:00 2001 From: Maciej W. Rozycki Date: Fri, 13 Nov 2015 00:47:08 +0000 Subject: MIPS: math-emu: Add IEEE Std 754-2008 ABS.fmt and NEG.fmt emulation Implement IEEE Std 754-2008 non-arithmetic ABS.fmt and NEG.fmt emulation wired to the state of the FCSR.ABS2008 bit. In the non-arithmetic mode the sign bit is altered according to the operation requested regardless of the datum encoded in the input operand, no other bits are changed, the resulting bit pattern is written to the output operand and no exception is ever signalled. Signed-off-by: Maciej W. Rozycki Cc: Andrew Morton Cc: Matthew Fortune Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/11476/ Signed-off-by: Ralf Baechle --- arch/mips/math-emu/dp_simple.c | 38 +++++++++++++++++++++++++------------- 1 file changed, 25 insertions(+), 13 deletions(-) (limited to 'arch/mips/math-emu/dp_simple.c') diff --git a/arch/mips/math-emu/dp_simple.c b/arch/mips/math-emu/dp_simple.c index 926d56bf37f2..eb96485ed939 100644 --- a/arch/mips/math-emu/dp_simple.c +++ b/arch/mips/math-emu/dp_simple.c @@ -23,27 +23,39 @@ union ieee754dp ieee754dp_neg(union ieee754dp x) { - unsigned int oldrm; union ieee754dp y; - oldrm = ieee754_csr.rm; - ieee754_csr.rm = FPU_CSR_RD; - y = ieee754dp_sub(ieee754dp_zero(0), x); - ieee754_csr.rm = oldrm; + if (ieee754_csr.abs2008) { + y = x; + DPSIGN(y) = !DPSIGN(x); + } else { + unsigned int oldrm; + + oldrm = ieee754_csr.rm; + ieee754_csr.rm = FPU_CSR_RD; + y = ieee754dp_sub(ieee754dp_zero(0), x); + ieee754_csr.rm = oldrm; + } return y; } union ieee754dp ieee754dp_abs(union ieee754dp x) { - unsigned int oldrm; union ieee754dp y; - oldrm = ieee754_csr.rm; - ieee754_csr.rm = FPU_CSR_RD; - if (DPSIGN(x)) - y = ieee754dp_sub(ieee754dp_zero(0), x); - else - y = ieee754dp_add(ieee754dp_zero(0), x); - ieee754_csr.rm = oldrm; + if (ieee754_csr.abs2008) { + y = x; + DPSIGN(y) = 0; + } else { + unsigned int oldrm; + + oldrm = ieee754_csr.rm; + ieee754_csr.rm = FPU_CSR_RD; + if (DPSIGN(x)) + y = ieee754dp_sub(ieee754dp_zero(0), x); + else + y = ieee754dp_add(ieee754dp_zero(0), x); + ieee754_csr.rm = oldrm; + } return y; } -- cgit v1.2.3-55-g7522