libdecnumber: Introduce decNumberFrom[U]Int64

Introduce two conversion functions to the libdecnumber library.
These conversions transform 64 bit integers to the internal decNumber
representation.  Both a signed and unsigned version is added.

Signed-off-by: Tom Musta <tommusta@gmail.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
libdecnumber: Introduce decNumberIntegralToInt64

Introduce a new conversion function to the libdecnumber library.
This function converts a decNumber to a signed 64-bit integer.
In order to support 64-bit integers (which may have up to 19
decimal digits), the existing "powers of 10" array is expanded
from 10 to 19 entries.

Signed-off-by: Tom Musta <tommusta@gmail.com>
[agraf: fix 32bit host compile]
Signed-off-by: Alexander Graf <agraf@suse.de>
libdecnumber: Fix decNumberSetBCD

Fix a simple bug in the decNumberSetBCD() function.  This function
encodes a decNumber with "n" BCD digits.  The original code erroneously
computed the number of declets from the dn argument, which is the output
decNumber value, and hence may contain garbage.  Instead, the input "n"
value is used.

Signed-off-by: Tom Musta <tommusta@gmail.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
target-ppc: Define FPR Pointer Type for Helpers

Define a floating pointer register pointer type in the PowerPC
helper header.  The type will be used to pass FPR register operands
to Decimal Floating Point (DFP) helpers.  A pointer is used because
the quad word forms of PowerPC DFP instructions operate on adjacent
pairs of floating point registers and thus can be thought of as
arrays of length 2.

Signed-off-by: Tom Musta <tommusta@gmail.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
target-ppc: Introduce Generator Macros for DFP Arithmetic Forms

Add general support for generators of PowerPC Decimal Floating Point helpers.

Some utilities are annotated with GCC attribute unused in order to preserve
build bisection.  These annotations will be removed in later patches.

Signed-off-by: Tom Musta <tommusta@gmail.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
target-ppc: Introduce Decoder Macros for DFP

Add decoder macros for the various Decimal Floating Point
instruction forms.  Illegal instruction masks are used to not only
guard against reserved instruction field use, but also to catch
illegal quad word forms that use odd-numbered floating point registers.

Signed-off-by: Tom Musta <tommusta@gmail.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
target-ppc: Introduce DFP Helper Utilities

Add a new file (dfp_helper.c) to the PowerPC implementation for Decimal Floating
Point (DFP) emulation.  This first version of the file declares a structure that
will be used by DFP helpers.  It also implements utilities that will initialize
such a structure for either a long (64 bit) DFP instruction or an extended (128
bit, aka "quad") instruction.

Some utility functions are annotated with the unused attribute in order to preserve
build bisection.

Signed-off-by: Tom Musta <tommusta@gmail.com>
[agraf: Add never reached assert on dfp_prepare_rounding_mode()]
Signed-off-by: Alexander Graf <agraf@suse.de>
target-ppc: Introduce DFP Post Processor Utilities

Add post-processing utilities to the PowerPC Decimal Floating Point
(DFP) helper code.  Post-processors are small routines that execute
after a preliminary DFP result is computed.  They are used, among other
things, to compute status bits.

This change defines a function type for post processors as well as a
generic routine to run a list (array) of post-processors.

Actual post-processor implementations will be added as needed by specific
DFP helpers in subsequent changes.

Some routines are annotated with the GCC unused attribute in order to
preserve build bisection.  The annotation will be removed in subsequent
patches.

Signed-off-by: Tom Musta <tommusta@gmail.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
target-ppc: Introduce DFP Add

Add emulation of the PowerPC Decimal Floating Point Add instructions dadd[q][.]

Various GCC unused annotations are removed since it is now safe to remove them.

Signed-off-by: Tom Musta <tommusta@gmail.com>
[agraf: move brace in function definition]
Signed-off-by: Alexander Graf <agraf@suse.de>
target-ppc: Introduce DFP Subtract

Add emulation of the PowerPC Decimal Floating Point Subtract instructions
dsub[q][.]

Signed-off-by: Tom Musta <tommusta@gmail.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
target-ppc: Introduce DFP Multiply

Add emulation of the PowerPC Decimal Floating Point Multiply instructions
dmul[q][.]

Signed-off-by: Tom Musta <tommusta@gmail.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
target-ppc: Introduce DFP Divide

Add emulation of the PowerPC Decimal Floating Point Divide instructions
ddiv[q][.]

Signed-off-by: Tom Musta <tommusta@gmail.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
target-ppc: Introduce DFP Compares

Add emulation of the PowerPC Decimal Floating Point Compare instructions
dcmpu[q] and dcmpo[q].

Signed-off-by: Tom Musta <tommusta@gmail.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
target-ppc: Introduce DFP Test Data Class

Add emulation of the PowerPC Decimal Floating Point Test Data Class
instructions dtstdc[q][.].

Signed-off-by: Tom Musta <tommusta@gmail.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
target-ppc: Introduce DFP Test Data Group

Add emulation of the PowerPC Decimal Floating Point Test Data
Group instructions dtstdg[q][.].

Signed-off-by: Tom Musta <tommusta@gmail.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
target-ppc: Introduce DFP Test Exponent

Add emulation of the PowerPC Decimal Floating Point Test Exponent
instructions dtstex[q][.].

Signed-off-by: Tom Musta <tommusta@gmail.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
target-ppc: Introduce DFP Test Significance

Add emulation of the PowerPC Decimal Floating Point Test Significance
instructions dtstsf[q][.].

Signed-off-by: Tom Musta <tommusta@gmail.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
target-ppc: Introduce DFP Quantize

Add emulation of the PowerPC Decimal Floating Point Quantize instructions
dquai[q][.] and dqua[q][.].

Signed-off-by: Tom Musta <tommusta@gmail.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
target-ppc: Introduce DFP Reround

Add emulation of the PowerPC Decimal Floating Point Reround instructions
drrnd[q][.].

Signed-off-by: Tom Musta <tommusta@gmail.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
target-ppc: Introduce DFP Round to Integer

Add emulation of the PowerPC Decimal Floating Point (DFP) Round
to FP Integer With Inexact (drintx[q][.]) and DFP Round to FP
Integer Without Inexact (drintn[q][.]) instructions.

Signed-off-by: Tom Musta <tommusta@gmail.com>
Signed-off-by: Alexander Graf <agraf@suse.de>