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authorAleksandar Markovic <aleksandar.markovic@imgtec.com>2017-06-19 17:50:12 +0200
committerRalf Baechle <ralf@linux-mips.org>2017-06-28 02:54:30 +0200
commitddbfff7429a75d954bf5bdff9f2222bceb4c236a (patch)
tree89a95f0e4b2d3859fd900e9b1e74a25887bb2355
parent25d8b92e0af75d72ce8b99e63e5a449cc0888efa (diff)
MIPS: math-emu: Handle zero accumulator case in MADDF and MSUBF separately
If accumulator value is zero, just return the value of previously calculated product. This brings logic in MADDF/MSUBF implementation closer to the logic in ADD/SUB case. Signed-off-by: Miodrag Dinic <miodrag.dinic@imgtec.com> Signed-off-by: Goran Ferenc <goran.ferenc@imgtec.com> Signed-off-by: Aleksandar Markovic <aleksandar.markovic@imgtec.com> Cc: James.Hogan@imgtec.com Cc: Paul.Burton@imgtec.com Cc: Raghu.Gandham@imgtec.com Cc: Leonid.Yegoshin@imgtec.com Cc: Douglas.Leung@imgtec.com Cc: Petar.Jovanovic@imgtec.com Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/16512/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
-rw-r--r--arch/mips/math-emu/dp_maddf.c5
-rw-r--r--arch/mips/math-emu/sp_maddf.c5
2 files changed, 8 insertions, 2 deletions
diff --git a/arch/mips/math-emu/dp_maddf.c b/arch/mips/math-emu/dp_maddf.c
index 4a2d03c72959..caa62f20a888 100644
--- a/arch/mips/math-emu/dp_maddf.c
+++ b/arch/mips/math-emu/dp_maddf.c
@@ -54,7 +54,7 @@ static union ieee754dp _dp_maddf(union ieee754dp z, union ieee754dp x,
return ieee754dp_nanxcpt(z);
case IEEE754_CLASS_DNORM:
DPDNORMZ;
- /* QNAN is handled separately below */
+ /* QNAN and ZERO cases are handled separately below */
}
switch (CLPAIR(xc, yc)) {
@@ -210,6 +210,9 @@ static union ieee754dp _dp_maddf(union ieee754dp z, union ieee754dp x,
}
assert(rm & (DP_HIDDEN_BIT << 3));
+ if (zc == IEEE754_CLASS_ZERO)
+ return ieee754dp_format(rs, re, rm);
+
/* And now the addition */
assert(zm & DP_HIDDEN_BIT);
diff --git a/arch/mips/math-emu/sp_maddf.c b/arch/mips/math-emu/sp_maddf.c
index a8cd8b4f235e..c91d5e5d9b5f 100644
--- a/arch/mips/math-emu/sp_maddf.c
+++ b/arch/mips/math-emu/sp_maddf.c
@@ -54,7 +54,7 @@ static union ieee754sp _sp_maddf(union ieee754sp z, union ieee754sp x,
return ieee754sp_nanxcpt(z);
case IEEE754_CLASS_DNORM:
SPDNORMZ;
- /* QNAN is handled separately below */
+ /* QNAN and ZERO cases are handled separately below */
}
switch (CLPAIR(xc, yc)) {
@@ -203,6 +203,9 @@ static union ieee754sp _sp_maddf(union ieee754sp z, union ieee754sp x,
}
assert(rm & (SP_HIDDEN_BIT << 3));
+ if (zc == IEEE754_CLASS_ZERO)
+ return ieee754sp_format(rs, re, rm);
+
/* And now the addition */
assert(zm & SP_HIDDEN_BIT);