The right-operand of shift expressions is self-determined, but we still
need to run a test_width to get the PExpr decorated with types and
expression widths.
The l-value doesn't really constrain the size of unsized expressions
because there are possible sub-expressions that may pull high bits
down to the low bits. (Divide, for example.)
If either of the operands of a ternary expression are unsigned, then
both are treated as unsigned. It works just like a binary expression
in that regard.
The results of comparisons are unsigned, but the arguments may be signed
and the calculation performed may be signed. Handle the padding properly
for comparisons so that the math is properly signed.
Later passes need the intermediate results for width and size so that
some special cases, were self-determined arguments occur, can be
processed properly during elaboration. This can be especially tricky
and interesting for ternary expressions.
This patch fixes the expression width calculation for a multiply
operation with an unsized operation. The expression width needs
to be at least the minimum of the maximum multiply result width
and the width of an integer.
This patch removes all the checks for constant expressions performed
during the parsing phase, as these checks are (mostly) repeated during
elaboration. It adds the missing check in the elaboration phase (the
RHS of a register initialisation), and improves the error reporting
and error recovery in other checks.
This patch fixes pr2132552, which was caused by a fault in the parser
constant expression checking.
Multiply of any expression with constant 0 will always return zero.
We can handle this early, during elaboration, and save a lot of code
downstream the trouble.
Also, while we are at it, fix up test_width to re-test the left
expression width if the right expression width is unsized. This allows
for the left expression code to adapt to the unsized-ness of the
expression context.
There are cases where the r-value doesn't pad itself to the width
that is requested by the call to elaborate_expr. This impacts the
elaboration of PGAssign. Pad/sign extend as appropreate.
The arguments to bitwise operators are padded if *either* of the operands
is unsigned. This is according to the sign/unsigned expression rules
of Verilog, and also matches the behavior of the "Big-3."
The addition of UINT_MAX in netlist.cc requires #include <climits> when compiling with gcc-4.3.2.
I also noticed that commit 8704e3e used c style includes in c++ sources contrary to the style used in the rest of the c++ code and fixed those.
Simple error setting the expression width of the FALSE clause of a
ternary expression when the expression is short cuirted to false.
Fix a simple error where the type of a system function is not returned
through the test_width function.
The arguments to user defined functions are self-determined. And if
the result is real valued, we can call them lossless self-determined.
Treat these arguments like r-value elaboration for assignments.
Also clean up the binary divide elaboration a little bit.
Also, floating point literals are unsized with width==1.
Widths of real values are always 1. When paired with vectorable types
in expressions, the vectorable type is processed as losslessly self-
determined. ("unsized" in the test_width methods.)
Don't force the expression with to be different from the l-value if the
l-value is the immediate destination. This saves the effort of handling
overly wide constant values in simple cases.
Also, in determined contexts, signed unary minus does not need to pad the
width of the expression.
the PGAssign elaborate method used the test_width to get the width
of the r-value expression. This should be completely sufficient to
get the width of the expression, so always use a defined width to
elaborate the expression.
When ternary expressions are self-determined, use the test_width
method to get a proper reading of the expression width. Also improve
the test_width method to handle unsized operands.
The true and false expression clauses must have compatible types,
which are not necesarily identical. In particular, VT_BOOL and
VT_LOGIC are compatible for the purposes of ternary arguments. The
test in NetETernary::synthesize was incorrect.
In the process, fix the type handling of NetConst objects to allow
for IVL_VT_BOOL constants. This is information that the downstream
may find useful, so should be handled correctly.
Nothing to do with tab width! Eliminates useless
trailing spaces and tabs, and nearly all <space><tab>
pairings. No change to derived files (e.g., .vvp),
non-master files (e.g., lxt2_write.c) or the new tgt-vhdl
directory.
Low priority, simple entropy reduction. Please apply
unless it deletes some steganographic content you want
to keep.
In continuous assignment, the width of the expression needs to come
from the expression itself, and not just from the width of the l-value.
Use the PExpr::test_width method to get the width of the expression
to pass to the elaborate.
When the condition expression of a ternary is constant 1 or 0, we can
short-circuit the elaboration by only processing the clause (true or
false) that we need. This saves compile time and execution time.
It is possible for the left operand of a left shift to be not known
early during elaborate expression. In that case, make a punt expression
and expect it to be resolved later.
The expr:::synthesize methods need not deal with saturating left or
right shifts if they are dealt with early, in elaborate_expr methods.
So the elaborate_expr for shift takes on much more responsibility.
In signed contextx, the right shift and unary minus expressions need
to be sign extended before they operate, otherwise there may be bad
results in the high bits in the greater context.
The NetBranch object is connected, but not like an object, so the
NetPins object base class is factored out from NetObj to handle the
connectivity, and the NetBranch class uses the NetPins to connect a
branch.
Also, account for the fact that nets with a discipline are by default
real-valued.
Detect function call expressions that turn out to be calls to the
access function of a nature. Elaborate the access function and stub
the emit code. This gets the access function just short of the code
generator.
Contribution statements have an l-value and r-value. Parse those
expressions into pform so that elaboration has something to work with.
In this process, this patch also changes the PECallFunction class to
use the vector template instead of the svector template. The latter
doesn't add anything over the STL vector template, so this is a start
of working the svector out.
Part select of an entire signal returns just the NetESignal itself,
but since part selects are always unsigned, even if the selected
signal is signed, we need to cast the NetESignal to unsigned first.
The part select of a vector is converted by the compiler during
elaboration to a 0-based canonical address. But since it is legal
to address bits below the LSB, the canonical address can be negative.
So make the part select base for selecting from signals work with
signed arithmetic and make the code generator generate negative
indices when needed.
Part select of parameter names is fixed up to be structurally similar
to part select of signals, and also to behave similarly. (Though not
identically, for reason.)
Part selects to signals are allowed to be off the ends of the signal
itself. The bits that are beyond the vector return X. This may mean
creating constant X bits on one or both ends of the result.
A recent change to sb_to_idx() made it return a signed value
where it previously returned an unsigned value. This patch adds
explicit casts to remove the two signed vs unsigned comparison
warning messages.
Fix
elab_expr.cc:1561: warning: comparison between signed and unsigned integer expressions
caused by revised prototype of NetNet::sb_to_idx() in
commit dfb7bf5211
IEEE1364 has specific names for the various generations of Verilog that
are supported. Icarus Verilog should stick to those names for selection
the language feature set.
In the process, the extensions that were tied to the 2x generations
are pulled out out and given their own enable flags. The makes all the
feature control more regular and understandable.
Implement in behavioral the abs/min/max operators for real values.
The parser treats these builtin functions as operators, unary or
binary, and elaborates them appropriately.
Also add enough code generator support to handle real valued expressions
in thread context.
1364-2001 does not allow a replication count of zero, but
1364-2005 allows them when the replication is enclosed in
a concatenation with other valid bits. This patch adds
code to perform these checks for procedural expressions.
Because of the NetNet object must have a width greater
than zero a replication used in a continuous assignment
can never have a count of zero.
Logical and/or take as inputs condition expressions, which are scalar
expressions. Be sure to reduce vectors using proper logic to get the
right condition value.
When left-shifting unsized constants in self-determined contexts, the
constant value is normally pared down to its minimum required width.
But this practically guarantees loss of bits. Instead, detect this
special case and give the unsized constant a width of an integer.
Still allow for the super-special case that the shifted value and the
shift amount are constants. In that case, the result width (and value)
can be calculated precisely and there is no need to resort to default
widths.
Binary bit based operators were not padding arguments if they had
different widths. The reduction operators and ! were not correctly
evaluating their arguments in a self-determined context.
This patch reworks much of the ternary code to short circuit when
possible and supports real values better. It adds a blend operator
for real values that returns 0.0 when the values differ and the value
when they match. This deviates slightly from the standard which
specifies that the value for reals is always 0.0 when the conditional
is 'bx. There are also a couple bug fixes.
These fixes have not been ported to continuous assignments yet.
Ternary operators used at compile time and in procedural assignments
should be complete (short circuit and support real values).
This patch adds bit based power support to normal expressions.
It also pushes the constant unsigned bit based calculation to
the runtime until the bit based method can be copied to the
compiler. Continuous assignments also need to use this type
of calculation.
This patch adds a check and prints a warning message when the power
operator is used with unsigned bit based values. It also fixes a couple
of typos and adds an asserts if the above power operator happens to
get to the tgt-vvp back end.
The compiler attempts to precalculate the results of <= comparisons.
Fix a few corner cases where the arguments are signed. Also fix the
important test of constant against non-constant where we try to test
if the non-constant value can possibly make the test fail.
Rework the handling of file names to use a perm_string heap to hold
the file names, instead of the custom file name heap in the lexor.
Also rename the get_line to get_fileline to reflect its real duties.
This latter chage touched a lot of files.
Comparison operands are signed only of both operands are signed.
If one is unsigned, then they both are unsigned. This does not
affect the signedness of the comparison itself, which is unsigned.
Signed-off-by: Stephen Williams <steve@icarus.com>
Fixed some signed/unsigned warnings, including one that caused an
actual runtime error if not dealt with safely.
Signed-off-by: Stephen Williams <steve@icarus.com>
The argument to $unsigned is self-determined no matter what the
context the $unsigned itself is in. This is important only where
the result can be negative but the result width is context-determined.
Do ocntext fitting manually to prevent the context fitting it and
affecting the expression argument.
Signed-off-by: Stephen Williams <steve@icarus.com>
Fix the handling of expressions that have unsized integers and are
in self determined context. Unsized integers are generally assumed
to have at least 32bits.
Signed-off-by: Stephen Williams <steve@icarus.com>
In expressions, user defined functions have a clearly defined
width and the test_width expression needs to express that. Note
that the $signed/$unsigned functions are special and magical.
Signed-off-by: Stephen Williams <steve@icarus.com>
distinguish between self-determined and value-preserving when
evaluating constants that are arguments to concatenations.
Signed-off-by: Stephen Williams <steve@icarus.com>
This fixes r-value type references to memory words for memories
that have a non-zero base address. Elaborate the expression
needed to get the canonical word index.
Real value are vector width of 1, fix real literal to reflect this.
fix leaking real registers in code generation for function arguments.
Load of signal should handle conversion from real to vector. Function
arguments, type vector passed a real value, are an example where this
comes up.
Signed-off-by: Stephen Williams <steve@icarus.com>
Stephen Williams
Martin Whitaker
Jared Casper
Cary R
Larry Doolittle
Martin Whitaker
steve