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2017-12-12MIPS: math-emu: Mark fall throughs in switch statements with a commentAleksandar Markovic
Mark intentional fall throughs in switch statements with a consistent comment. In most of the cases, a new comment line containing text "fall through" is inserted. In some of the cases, existing comment contained a variation of the text "fall through" (for example, "FALL THROUGH" or "drop through"). In such cases, the existing comment is modified to contain "fall through". Lastly, in two cases, code segments were described in comments as "fall througs", but were in reality "breaks out" of switch statement. In such cases, existing comments are accordingly modified. Apart from making code easier to follow and debug, this change enables some static code analysers to interpret newly inserted comments as their annotations (and, therefore, not issue warnings of type "fall through in switch statement", which is desireable, since marked fallthroughs are intentional). Signed-off-by: Aleksandar Markovic <aleksandar.markovic@mips.com> Cc: Douglas Leung <douglas.leung@mips.com> Cc: Goran Ferenc <goran.ferenc@mips.com> Cc: James Hogan <james.hogan@mips.com> Cc: Maciej W. Rozycki <macro@mips.com> Cc: Manuel Lauss <manuel.lauss@gmail.com> Cc: Miodrag Dinic <miodrag.dinic@mips.com> Cc: Paul Burton <paul.burton@mips.com> Cc: Petar Jovanovic <petar.jovanovic@mips.com> Cc: Raghu Gandham <raghu.gandham@mips.com> Cc: linux-kernel@vger.kernel.org Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/17588/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2017-12-12MIPS: math-emu: Declare function srl128() as staticAleksandar Markovic
Declare function srl128() as static, since it it used just locally to the source file. This also removes a sparse warning for corresponding file. Signed-off-by: Aleksandar Markovic <aleksandar.markovic@mips.com> Cc: Douglas Leung <douglas.leung@mips.com> Cc: Goran Ferenc <goran.ferenc@mips.com> Cc: James Hogan <james.hogan@mips.com> Cc: Miodrag Dinic <miodrag.dinic@mips.com> Cc: Paul Burton <paul.burton@mips.com> Cc: Petar Jovanovic <petar.jovanovic@mips.com> Cc: Raghu Gandham <raghu.gandham@mips.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/17585/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2017-12-12MIPS: math-emu: Avoid definition duplication for macro DPXMULT()Aleksandar Markovic
Avoid duplicate definition of macro DPXMULT(). Move its definition to a header. Signed-off-by: Aleksandar Markovic <aleksandar.markovic@mips.com> Cc: Douglas Leung <douglas.leung@mips.com> Cc: Goran Ferenc <goran.ferenc@mips.com> Cc: James Hogan <james.hogan@mips.com> Cc: Miodrag Dinic <miodrag.dinic@mips.com> Cc: Paul Burton <paul.burton@mips.com> Cc: Petar Jovanovic <petar.jovanovic@mips.com> Cc: Raghu Gandham <raghu.gandham@mips.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/17584/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2017-11-07MIPS: math-emu: Use preferred flavor of unsigned integer declarationsAleksandar Markovic
Fix occurences of unsigned integer variable declarations that are not preferred by standards of checkpatch scripts. This removes a significant number of checkpatch warnings for files in math-emu directory (several files become completely warning-free), and thus makes easier to spot (now and in the future) other, perhaps more significant, checkpatch errors and warnings. Signed-off-by: Aleksandar Markovic <aleksandar.markovic@mips.com> Reviewed-by: James Hogan <jhogan@kernel.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Douglas Leung <douglas.leung@mips.com> Cc: Goran Ferenc <goran.ferenc@mips.com> Cc: "Maciej W. Rozycki" <macro@imgtec.com> Cc: Manuel Lauss <manuel.lauss@gmail.com> Cc: Miodrag Dinic <miodrag.dinic@mips.com> Cc: Paul Burton <paul.burton@mips.com> Cc: Petar Jovanovic <petar.jovanovic@mips.com> Cc: Raghu Gandham <raghu.gandham@mips.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/17582/ Signed-off-by: James Hogan <jhogan@kernel.org>
2017-08-29MIPS: math-emu: <MADDF|MSUBF>.D: Fix accuracy (64-bit case)Douglas Leung
Implement fused multiply-add with correct accuracy. Fused multiply-add operation has better accuracy than respective sequential execution of multiply and add operations applied on the same inputs. This is because accuracy errors accumulate in latter case. This patch implements fused multiply-add with the same accuracy as it is implemented in hardware, using 128-bit intermediate calculations. One test case example (raw bits) that this patch fixes: MADDF.D fd,fs,ft: fd = 0x00000ca000000000 fs = ft = 0x3f40624dd2f1a9fc Fixes: e24c3bec3e8e ("MIPS: math-emu: Add support for the MIPS R6 MADDF FPU instruction") Fixes: 83d43305a1df ("MIPS: math-emu: Add support for the MIPS R6 MSUBF FPU instruction") Signed-off-by: Douglas Leung <douglas.leung@imgtec.com> 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: Douglas Leung <douglas.leung@imgtec.com> Cc: Bo Hu <bohu@google.com> Cc: James Hogan <james.hogan@imgtec.com> Cc: Jin Qian <jinqian@google.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: Petar Jovanovic <petar.jovanovic@imgtec.com> Cc: Raghu Gandham <raghu.gandham@imgtec.com> Cc: <stable@vger.kernel.org> # 4.7+ Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/16891/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2017-08-29MIPS: math-emu: <MADDF|MSUBF>.<D|S>: Clean up "maddf_flags" enumerationAleksandar Markovic
Fix definition and usage of "maddf_flags" enumeration. Avoid duplicate definition and apply more common capitalization. This patch does not change any scenario. It just makes MADDF and MSUBF emulation code more readable and easier to maintain, and hopefully prevents future bugs as well. 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> Reviewed-by: James Hogan <james.hogan@imgtec.com> Cc: Bo Hu <bohu@google.com> Cc: Douglas Leung <douglas.leung@imgtec.com> Cc: Jin Qian <jinqian@google.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: Petar Jovanovic <petar.jovanovic@imgtec.com> Cc: Raghu Gandham <raghu.gandham@imgtec.com> Cc: <stable@vger.kernel.org> # 4.7+ Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/16889/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2017-08-29MIPS: math-emu: <MADDF|MSUBF>.<D|S>: Fix some cases of zero inputsAleksandar Markovic
Fix the cases of <MADDF|MSUBF>.<D|S> when any of two multiplicands is +0 or -0, and the third input is also +0 or -0. Depending on the signs of inputs, certain special cases must be handled. A relevant example: MADDF.S fd,fs,ft: If fs contains +0.0, ft contains -0.0, and fd contains 0.0, fd is going to contain +0.0 (without this patch, it used to contain -0.0). Fixes: e24c3bec3e8e ("MIPS: math-emu: Add support for the MIPS R6 MADDF FPU instruction") Fixes: 83d43305a1df ("MIPS: math-emu: Add support for the MIPS R6 MSUBF FPU instruction") 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> Reviewed-by: James Hogan <james.hogan@imgtec.com> Cc: Bo Hu <bohu@google.com> Cc: Douglas Leung <douglas.leung@imgtec.com> Cc: Jin Qian <jinqian@google.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: Petar Jovanovic <petar.jovanovic@imgtec.com> Cc: Raghu Gandham <raghu.gandham@imgtec.com> Cc: <stable@vger.kernel.org> # 4.7+ Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/16888/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2017-08-29MIPS: math-emu: <MADDF|MSUBF>.<D|S>: Fix some cases of infinite inputsAleksandar Markovic
Fix the cases of <MADDF|MSUBF>.<D|S> when any of two multiplicands is infinity. The correct behavior in such cases is affected by the nature of third input. Cases of addition of infinities with opposite signs and subtraction of infinities with same signs may arise and must be handles separately. Also, the value od flags argument (that determines whether the instruction is MADDF or MSUBF) affects the outcome. Relevant examples: MADDF.S fd,fs,ft: If fs contains +inf, ft contains +inf, and fd contains -inf, fd is going to contain indef (without this patch, it used to contain -inf). MSUBF.S fd,fs,ft: If fs contains +inf, ft contains 1.0, and fd contains +0.0, fd is going to contain -inf (without this patch, it used to contain +inf). Fixes: e24c3bec3e8e ("MIPS: math-emu: Add support for the MIPS R6 MADDF FPU instruction") Fixes: 83d43305a1df ("MIPS: math-emu: Add support for the MIPS R6 MSUBF FPU instruction") Signed-off-by: Douglas Leung <douglas.leung@imgtec.com> 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> Reviewed-by: James Hogan <james.hogan@imgtec.com> Cc: Douglas Leung <douglas.leung@imgtec.com> Cc: Bo Hu <bohu@google.com> Cc: Jin Qian <jinqian@google.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: Petar Jovanovic <petar.jovanovic@imgtec.com> Cc: Raghu Gandham <raghu.gandham@imgtec.com> Cc: <stable@vger.kernel.org> # 4.7+ Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/16887/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2017-08-29MIPS: math-emu: <MADDF|MSUBF>.<D|S>: Fix NaN propagationAleksandar Markovic
Fix the cases of <MADDF|MSUBF>.<D|S> when any of three inputs is any NaN. Correct behavior of <MADDF|MSUBF>.<D|S> fd, fs, ft is following: - if any of inputs is sNaN, return a sNaN using following rules: if only one input is sNaN, return that one; if more than one input is sNaN, order of precedence for return value is fd, fs, ft - if no input is sNaN, but at least one of inputs is qNaN, return a qNaN using following rules: if only one input is qNaN, return that one; if more than one input is qNaN, order of precedence for return value is fd, fs, ft The previous code contained correct handling of some above cases, but not all. Also, such handling was scattered into various cases of "switch (CLPAIR(xc, yc))" statement, and elsewhere. With this patch, this logic is placed in one place, and "switch (CLPAIR(xc, yc))" is significantly simplified. A relevant example: MADDF.S fd,fs,ft: If fs contains qNaN1, ft contains qNaN2, and fd contains qNaN3, fd is going to contain qNaN3 (without this patch, it used to contain qNaN1). Fixes: e24c3bec3e8e ("MIPS: math-emu: Add support for the MIPS R6 MADDF FPU instruction") Fixes: 83d43305a1df ("MIPS: math-emu: Add support for the MIPS R6 MSUBF FPU instruction") 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> Reviewed-by: James Hogan <james.hogan@imgtec.com> Cc: Bo Hu <bohu@google.com> Cc: Douglas Leung <douglas.leung@imgtec.com> Cc: Jin Qian <jinqian@google.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: Petar Jovanovic <petar.jovanovic@imgtec.com> Cc: Raghu Gandham <raghu.gandham@imgtec.com> Cc: <stable@vger.kernel.org> # 4.7+ Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/16886/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2017-06-28MIPS: math-emu: Handle zero accumulator case in MADDF and MSUBF separatelyAleksandar Markovic
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>
2016-05-13MIPS: math-emu: Fix code indentationPaul Burton
A line incrementing the re variable was indented a level too deep in ieee754dp_mul, making the code unclear to read. Fix the indentation. This appears to have been copied verbatim along with the rest of the multiplication code to ieee754dp_maddf, now _dp_maddf, too so fix the indentation there too. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/13158/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-05-13MIPS: math-emu: Fix bit-width in ieee754dp_{mul, maddf, msubf} commentsPaul Burton
A comment in ieee754dp_mul indicates that the code is about to perform a 32b x 32b multiplication & keep the high 32b of the result. It appears this was copied from the single-precision multiplication code, since the code actually goes on to perform a 64b x 64b multiplication & keep the high 64b of the result. Fix the comment to indicate 64b. It appears also that this comment was copied verbatim along with the rest of the multiplication code into ieee754dp_maddf, which has since been renamed _dp_maddf. Fix the same issue there. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/13157/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-05-13MIPS: math-emu: Add z argument macrosPaul Burton
Introduce macros for handling the "z" argument to maddf & msubf, making its handling consistent with that of the "x" & "y" arguments rather than open-coding equivalents. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Cc: Maciej W. Rozycki <macro@imgtec.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/13156/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2016-05-13MIPS: math-emu: Unify ieee754dp_m{add,sub}fPaul Burton
The code for emulating MIPSr6 madd.d & msub.d instructions has previously been implemented as 2 different functions, namely ieee754dp_maddf & ieee754dp_msubf. The difference in behaviour of these 2 instructions is merely the sign of the product, so we can easily share the code implementing them. Do this for the double precision variant, removing the original ieee754dp_msubf in favor of reusing the code from ieee754dp_maddf. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/13155/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-09-03MIPS: math-emu: Add support for the MIPS R6 MADDF FPU instructionMarkos Chandras
MIPS R6 introduced the following instruction: Floating Point Fused Multiply Add: MADDF.fmt To perform a fused multiply-add of FP values. MADDF.fmt: FPR[fd] = FPR[fd] + (FPR[fs] x FPR[ft]) Signed-off-by: Markos Chandras <markos.chandras@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/10956/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>