The underflow and inexact exceptions are not mutually exclusive.
Check for both of them. Tidy the reset of FPSCR[FI].
Fixes: https://bugs.launchpad.net/bugs/1841442
Reported-by: Paul Clarke <pc@us.ibm.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Paul Clarke <pc@us.ibm.com>
Message-Id: <20190826165434.18403-2-richard.henderson@linaro.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
The xscvdpspn instruction implements a non-arithmetic conversion.
In particular, NaNs are not silenced and rounding is not performed.
Rewrite to match the pseudocode for ConvertDPtoSP_NS() in the
Power 3.0B manual.
Signed-off-by: Paul A. Clarke <pc@us.ibm.com>
Message-Id: <1566321964-1447-1-git-send-email-pc@us.ibm.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
[dwg: Replaced description with clearer version from rth]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
helper_todouble() was not properly converting any denormalized 32 bit
float to 64 bit double.
Fix-suggested-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paul A. Clarke <pc@us.ibm.com>
v2:
- Splitting patch "ppc: Three floating point fixes"; this is just one part.
- Original suggested "fix" was likely flawed. v2 is rewritten by
Richard Henderson (Thanks, Richard!); I reformatted the comments in a
couple of places, compiled, and tested.
Message-Id: <1566250936-14538-1-git-send-email-pc@us.ibm.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
helper_todouble() was not properly converting INFINITY from 32 bit
float to 64 bit double.
(Normalized operand conversion is unchanged, other than indentation.)
Signed-off-by: Paul A. Clarke <pc@us.ibm.com>
Message-Id: <1566242388-9244-1-git-send-email-pc@us.ibm.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
The POWER8 and POWER9 User's Manuals specify the implementation
behavior for what the ISA leaves "undefined" behavior for the
xscvdpspn and xscvdpsp instructions. This patch corrects the QEMU
implementation to match the hardware implementation for that case.
ISA 3.0B has xscvdpspn leaving its result in word 0 of the target register,
with the other words of the target register left "undefined".
The User's Manuals specify:
VSX scalar convert from double-precision to single-precision (xscvdpsp,
xscvdpspn).
VSR[32:63] is set to VSR[0:31].
So, words 0 and 1 both contain the result.
Note: this is important because GCC as of version 8 or so, assumes and takes
advantage of this behavior to optimize the following sequence:
xscvdpspn vs0,vs1
mffprwz r8,f0
ISA 3.0B has xscvdpspn leaving its result in word 0 of the target register,
and mffprwz expecting its input to come from word 1 of the source register.
This sequence fails with QEMU, as a shift is required between those two
instructions. However, since the hardware splats the result to both words 0
and 1 of its output register, the shift is not necessary.
Expect a future revision of the ISA to specify this behavior.
Signed-off-by: Paul A. Clarke <pc@us.ibm.com>
v2
- Splitting patch "ppc: Three floating point fixes"; this is just one part.
- Updated commit message to clarify behavior is documented in User's Manuals.
- Updated commit message to correct which words are in output and source of
xscvdpspn and mffprz.
- No source changes to this part of the original patch.
Message-Id: <1566236601-22954-1-git-send-email-pc@us.ibm.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
ISA 3.0B added a set of Floating-Point Status and Control Register (FPSCR)
instructions: mffsce, mffscdrn, mffscdrni, mffscrn, mffscrni, mffsl.
This patch adds support for 'mffsl'.
'mffsl' is identical to 'mffs', except it only returns mode, status, and enable
bits from the FPSCR.
On CPUs without support for 'mffsl' (below ISA 3.0), the 'mffsl' instruction
will execute identically to 'mffs'.
Note: I renamed FPSCR_RN to FPSCR_RN0 so I could create an FPSCR_RN mask which
is both bits of the FPSCR rounding mode, as defined in the ISA.
I also fixed a typo in the definition of FPSCR_FR.
Signed-off-by: Paul A. Clarke <pc@us.ibm.com>
v4:
- nit: added some braces to resolve a checkpatch complaint.
v3:
- Changed tcg_gen_and_i64 to tcg_gen_andi_i64, eliminating the need for a
temporary, per review from Richard Henderson.
v2:
- I found that I copied too much of the 'mffs' implementation.
The 'Rc' condition code bits are not needed for 'mffsl'. Removed.
- I now free the (renamed) 'tmask' temporary.
- I now bail early for older ISA to the original 'mffs' implementation.
Message-Id: <1565982203-11048-1-git-send-email-pc@us.ibm.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Introduce a new GEN_VSX_HELPER_VSX_MADD macro for the generator function which
enables the source and destination registers to be decoded at translation time.
This enables the determination of a or m form to be made at translation time so
that a single helper function can now be used for both variants.
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20190616123751.781-16-mark.cave-ayland@ilande.co.uk>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Rather than perform the VSR register decoding within the helper itself,
introduce a new GEN_VSX_HELPER_R2_AB macro which performs the decode based
upon rA and rB at translation time.
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20190616123751.781-13-mark.cave-ayland@ilande.co.uk>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Rather than perform the VSR register decoding within the helper itself,
introduce a new GEN_VSX_HELPER_R2 macro which performs the decode based
upon rD and rB at translation time.
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20190616123751.781-12-mark.cave-ayland@ilande.co.uk>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Rather than perform the VSR register decoding within the helper itself,
introduce a new GEN_VSX_HELPER_R3 macro which performs the decode based
upon rD, rA and rB at translation time.
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20190616123751.781-11-mark.cave-ayland@ilande.co.uk>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Rather than perform the VSR register decoding within the helper itself,
introduce a new GEN_VSX_HELPER_X1 macro which performs the decode based
upon xB at translation time.
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20190616123751.781-10-mark.cave-ayland@ilande.co.uk>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Rather than perform the VSR register decoding within the helper itself,
introduce a new GEN_VSX_HELPER_X2_AB macro which performs the decode based
upon xA and xB at translation time.
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20190616123751.781-9-mark.cave-ayland@ilande.co.uk>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Rather than perform the VSR register decoding within the helper itself,
introduce a new GEN_VSX_HELPER_X2 macro which performs the decode based
upon xT and xB at translation time.
With the previous change to the xscvqpdp generator and helper functions the
opcode parameter is no longer required in the common case and can be
removed.
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20190616123751.781-8-mark.cave-ayland@ilande.co.uk>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Rather than perform the VSR register decoding within the helper itself,
introduce a new generator and helper function which perform the decode based
upon xT and xB at translation time.
The xscvqpdp helper is the only 2 parameter xT/xB implementation that requires
the opcode to be passed as an additional parameter, so handling this separately
allows us to optimise the conversion in the next commit.
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20190616123751.781-7-mark.cave-ayland@ilande.co.uk>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Rather than perform the VSR register decoding within the helper itself,
introduce a new GEN_VSX_HELPER_X3 macro which performs the decode based
upon xT, xA and xB at translation time.
With the previous changes to the VSX_CMP generator and helper macros the
opcode parameter is no longer required in the common case and can be
removed.
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20190616123751.781-6-mark.cave-ayland@ilande.co.uk>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Rather than perform the VSR register decoding within the helper itself,
introduce a new VSX_CMP macro which performs the decode based upon xT, xA
and xB at translation time.
Subsequent commits will make the same changes for other instructions however
the xvcmp* instructions are different in that they return a set of flags to be
optionally written back to the crf[6] register. Move this logic from the
helper function to the generator function, along with the float_status update.
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20190616123751.781-5-mark.cave-ayland@ilande.co.uk>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Since commit 8a14d31b00 "target/ppc: switch fpr/vsrl registers so all VSX
registers are in host endian order" functions getVSR() and putVSR() which used
to convert the VSR registers into host endian order are no longer required.
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Message-Id: <20190616123751.781-2-mark.cave-ayland@ilande.co.uk>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Cleanup in the boilerplate that each target must define.
Replace ppc_env_get_cpu with env_archcpu. The combination
CPU(ppc_env_get_cpu) should have used ENV_GET_CPU to begin;
use env_cpu now.
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Having a separate, logical classifiation of numbers will
unify more error paths for different formats.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Use do_float_check_status directly, so that we don't get confused
about which return address we're using. And definitely don't use
helper_float_check_status.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
The always_inline trick only works if the function is always
called from the outer-most helper. But it isn't, so pass in
the outer-most return address. There's no need for a switch
statement whose argument is always a constant. Unravel the
switch and goto via more helpers.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Memory operations have no side effects on fp state.
The use of a "real" conversions between float64 and float32
would raise exceptions for SNaN and out-of-range inputs.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Divide by zero, exception taken, leaves the destination register
unmodified. Therefore we must raise the exception before returning
from the respective helpers.
>From helper_fre, divide by zero exception not taken, return the
documented +/- 0.5.
At the same time, tidy the invalid exception checking so that we
rely on softfloat for initial argument validation, and select the
kind of invalid operand exception only when we know we must.
At the same time, pass and return float64 values directly rather
than bounce through the CPU_DoubleU union.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Tidy the invalid exception checking so that we rely on softfloat for
initial argument validation, and select the kind of invalid operand
exception only when we know we must. Pass and return float64 values
directly rather than bounce through the CPU_DoubleU union.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Tidy the invalid exception checking so that we rely on softfloat for
initial argument validation, and select the kind of invalid operand
exception only when we know we must. Pass and return float64 values
directly rather than bounce through the CPU_DoubleU union.
Note that because we know float_flag_invalid was set, we do not have
to re-check the signs of the infinities.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Tidy the invalid exception checking so that we rely on softfloat for
initial argument validation, and select the kind of invalid operand
exception only when we know we must. Pass and return float64 values
directly rather than bounce through the CPU_DoubleU union.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Divide by zero, exception taken, leaves the destination register
unmodified. Therefore we must raise the exception before returning
from helper_fdiv. Move the check from do_float_check_status into
helper_fdiv.
At the same time, tidy the invalid exception checking so that we
rely on softfloat for initial argument validation, and select the
kind of invalid operand exception only when we know we must.
At the same time, pass and return float64 values directly rather
than bounce through the CPU_DoubleU union.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
While just setting the MSR bits is sufficient, we can tidy
the helper code by extracting the MSR test to a helper and
then forcing it true for user-only.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
The FPSCR[FI] bit indicates if the last floating point instruction had a result that was rounded. Each consecutive floating point instruction is suppose to set this bit to the correct value. What currently happens is this bit is not set as often as it should be. I have verified that this is the behavior of a real PowerPC 950. This patch fixes that problem by deciding to set this bit after each floating point instruction.
https://www.pdfdrive.net/powerpc-microprocessor-family-the-programming-environments-for-32-e3087633.html
Page 63 in table 2-4 is where the description of this bit can be found.
Signed-off-by: John Arbuckle <programmingkidx@gmail.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Fix the helper_fpscr_clrbit() function so it correctly sets the FEX
and VX bits.
Determining the value for the Floating Point Status and Control
Register's (FPSCR) FEX bit is suppose to be done like this:
FEX = (VX & VE) | (OX & OE) | (UX & UE) | (ZX & ZE) | (XX & XE))
It is described as "the logical OR of all the floating-point exception
bits masked by their respective enable bits". It was not implemented
correctly. The value of FEX would stay on even when all other bits
were set to off.
The VX bit is described as "the logical OR of all of the invalid
operation exceptions". This bit was also not implemented correctly. It
too would stay on when all the other bits were set to off.
My main source of information is an IBM document called:
PowerPC Microprocessor Family:
The Programming Environments for 32-Bit Microprocessors
Page 62 is where the FPSCR information is located.
This is an older copy than the one I use but it is still very useful:
https://www.pdfdrive.net/powerpc-microprocessor-family-the-programming-environments-for-32-e3087633.html
I use a G3 and G5 iMac to compare bit values with QEMU. This patch
fixed all the problems I was having with these bits.
Signed-off-by: John Arbuckle <programmingkidx@gmail.com>
[dwg: Re-wrapped commit message]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Only MIPS requires snan_bit_is_one to be variable. While we are
specializing softfloat behaviour, allow other targets to eliminate
this runtime check.
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: Yongbok Kim <yongbok.kim@mips.com>
Cc: David Gibson <david@gibson.dropbear.id.au>
Cc: Alexander Graf <agraf@suse.de>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Tested-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
As cpu.h is another typically widely included file which doesn't need
full access to the softfloat API we can remove the includes from here
as well. Where they do need types it's typically for float_status and
the rounding modes so we move that to softfloat-types.h as well.
As a result of not having softfloat in every cpu.h call we now need to
add it to various helpers that do need the full softfloat.h
definitions.
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
[For PPC parts]
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Use the helper routine float[32,64]_maddsub_update_excp() in VSX_MADD
macro.
Signed-off-by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Adds FPU_MADDSUB_UPDATE macro, this will be used for other routines
having float32/16
Signed-off-by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Current order of checking does not confirm with the spec
(ISA 3.0: MultiplyAddDP page-469). Change the order and make them
independent of each other.
For example: a = infinity, b = zero, c = SNaN, this should set both
VXIMZ and VXNAN
Signed-off-by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Use the softfloat api for fused multiply-add.
Introduce routine to set the FPSCR flags VXNAN, VXIMZ nad VMISI.
Signed-off-by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
xscvqpudz: VSX Scalar truncate & Convert Quad-Precision format to
Unsigned Doubleword format
xscvqpuwz: VSX Scalar truncate & Convert Quad-Precision format to
Unsigned Word format
Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
xsaddqpo: VSX Scalar Add Quad-Precision using round to Odd
xsmulqo: VSX Scalar Multiply Quad-Precision using round to Odd
xsdivqpo: VSX Scalar Divide Quad-Precision using round to Odd
xscvqpdpo: VSX Scalar round & Convert Quad-Precision format to
Double-Precision format using round to Odd
xssqrtqpo: VSX Scalar Square Root Quad-Precision using round to Odd
xssubqpo: VSX Scalar Subtract Quad-Precision using round to Odd
In addition, fix the invalid bitmask in the instruction encoding
of xssqrtqp[o].
Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
CC: Jose Ricardo Ziviani <joserz@linux.vnet.ibm.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
xststdcsp: VSX Scalar Test Data Class Single-Precision
xststdcdp: VSX Scalar Test Data Class Double-Precision
xststdcqp: VSX Scalar Test Data Class Quad-Precision
Signed-off-by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
