PR #257 was aggressively merged before all coding-style issues had
been commented on.  This addresses the issues that came up (except the
drive-by whitespace cleanup that was contained in PR #257 and would
require a force-push) in review.

This commit adds the following:
- infrastructure for Zfa (e.g., existence macro)
- support for the following instructions:
  + FLI.[HSD]
  + FMINM.[HSD] and FMAXM.[HSD]
  + FROUND.[HSD] and FROUNDNX.[HSD]
  + FMVH.X.D and FMVP.D.X
  + FLEQ.[HSD] and FLTQ.[HSD]
  + FCVTMOD.W.D

Note the following implementation details:

FMINM and FMAXM provide similar functionality to FMIN and FMAX,
differing only in their NaN-handling:
 * FMIN/FMAX return a canonical NaN only if both operands are a NaN
 * FMINM/FMAXM return a canonical Nan if any operand is a NaN
Consequently, the implementation is identical to FMIN/FMAX with only
the NaN-related tests changed.

FROUND instruction rounds a floating-point number in floating-point
register rs1 and writes that integer, represented as a floating-point
number to floating-point register rd while:
* Zero and infinite inputs are copied to rd unmodified.
* NaN inputs cause the invalid operation exception flag to be set.
FROUNDNX instruction is defined similarly, but also sets the inexact
exception flag if the input differs from the rounded result and is not
NaN.

FMVH.X.D instruction is available for RV32 only and moves bits 63:32
of floating-point register rs1 into integer register rd.

FMVP.D.X instruction is available for RV32 only and moves a
double-precision number from a pair of integer registers into a
floating-point register. Integer registers rs1 and rs2 supply bits
31:0 and 63:32, respectively.

FLEQ and FLTQ instructions are defined like the FLE and FLT
instructions, except that quiet NaN inputs do not cause the invalid
operation exception flag to be set.

The FCVTMOD.W.D instruction is defined similarly to the FCVT.W.D
instruction, with the following differences:
 * FCVTMOD.W.D always rounds towards zero.
 * Bits 31:0 are taken from the rounded, unbounded two's complement
   result, then sign-extended to XLEN bits and written to integer
   register rd.
 * Positive infinity, negative infinity and NaN are converted to zero.

Signed-off-by: Charalampos Mitrodimas <charalampos.mitrodimas@vrull.eu>
Signed-off-by: Philipp Tomsich <philipp.tomsich@vrull.eu>

This fixes a small bug in `mcounthinhibit`. In the current code if you set `mcountinhibit=1` then it inhibits the count of that CSR write, whereas the spec says that it should only apply to future instructions:

> Any CSR write takes effect after the writing instruction has otherwise completed.

- From the priviledged spec, section 3.1.10 Hardware Performance Monitor.

Changed the pmp initial misconfiguration check so that if the low and high range limit are the same then no pmp match

This implements the Zicond (conditional integer operations) extension,
as of version 1.0-draft-20230120.

The Zicond extension acts as a building block for branchless sequences
including conditional-arithmetic, conditional-logic and
conditional-select/move.
The following instructions constitute Zicond:
  - czero.eqz rd, rs1, rs2  =>  rd = (rs2 == 0) ? 0 : rs1
  - czero.nez rd, rs1, rs2  =>  rd = (rs2 != 0) ? 0 : rs1

See
  https://github.com/riscv/riscv-zicond/releases/download/v1.0-draft-20230120/riscv-zicond_1.0-draft-20230120.pdf


for the proposed specification and usage details.

Co-authored-by: Jessica Clarke <jrtc27@jrtc27.com>
Signed-off-by: Philipp Tomsich <philipp.tomsich@vrull.eu>

Only reporting the address (without data) on failures matches QEMU.
This also drops the call to rvfi_write from phys_mem_write since that
would result in (harmless) duplicate trace value updates.

Half-precision loads/stores should not be allowed if mstatus.FS is set to
0 to match single/double-precision ones.

fixed an issue with the -g switch which requires an argument. missing colon in string arg to getopt_long()

Signed-off-by: Rafael Sene <rafael@riscv.org>

This may be more readable and also matches the sail-cheri-riscv model.
For now this keeps ~ overloaded to accept bool, but in the future we may
want to consider removing it (which is what I did to find all uses
modified in this patch)

This is useful for the sail-cheri-riscv model, where we would like to
reuse C_ILLEGAL, but can't right now since it is current defined too late.

It is needed for https://github.com/CTSRD-CHERI/sail-cheri-riscv/pull/69

Ubuntu 18.04 is being sunset.

Sail tries to check for pattern match completeness and issues warnings
but this often gives false positives: see discussion at
https://github.com/rems-project/sail/issues/191 .  To suppress these
we add a wildcard case that raises an internal error.  There is
effectively no behaviour change as these would previously have
resulted in a match error at runtime and they should be unreachable
anyway.

At the same time we change the DOUBLE case in memory access paths to
allow for xlen > 64.

Following discussion on the PR I also changed internal_error to take a
file and line number as an argument to aid with debugging.

Fixes: https://github.com/riscv/sail-riscv/issues/194

This can now be found in the Sail repository.
Includes an update to sail-riscv.install

Revert "added 3 new command line switches (plus functionality):  -X/--enable-experimental-extensions, --enable-smepmp, --enable-zicond (#219)" (#220)

Reverts #219. Merged without code review and with many issues.

This reverts commit 43b81eaf.

added 3 new command line switches (plus functionality):  -X/--enable-experimental-extensions, --enable-smepmp, --enable-zicond (#219)

* added 3 command-line switches:  -X/--enable-experimental-extensions, --enable-Smepmp, --enable-Zicond

* example commit

* fixed some type warnings/errors (between int/bool)

Previously the decoding hook (`ext_post_decode_hook`) allowed models to
override the decoded `ast`. However, this is not sufficient if model
extension changes interpretation of fields. Additionally, the assembly
printing would always print assembly for the "baseline decode" which
resulted in incorrect trace output in the sail-cheri-riscv model.

With the new hook models can implement ext_decode()/ext_decode_compressed()
to return an `ast` and for encodings that are not adjusted fall back to
the default `encdec`/`encdec_compressed`.

Signed-off-by: Jan Henrik Weinstock <jan@mwa.re>

Signed-off-by: Jan Henrik Weinstock <jan@mwa.re>

Signed-off-by: Jan Henrik Weinstock <jan@mwa.re>

Signed-off-by: Jan Henrik Weinstock <jan@mwa.re>

This option causes handle_illegal to pass instbits as the value to set
for xtval, but instbits is never set so it ends up being 0 just as if
the option was never enabled. Fix this by initialising instbits during
fetch; we could make this conditional on whether the option is enabled
but that seems unnecessary and introduces tighter coupling.

Note that this option appears to have always been broken; when it was
originally added, instbits was only written two in two cases which were
both dead code and later removed in eb176111.

Closes: #173

After the last commit -fcommon is no longer required.

This reverts commit ffea7a39.

The sail C code generator will emit definions for these structs. The
duplicate definition linker error were worked around by adding -fcommon
in ffea7a39. This commit fixes the
underlying issue by declaring the variables as `extern`.

Merged after code review. Thanks everybody for helping.

* test: Ignore generated XML output

* run_tests: Build RVFI emulators too

Can't run tests with them though as they're built for direct instruction
injection (RVFI-DII) via an instruction stream over a network socket,
not fetching instructions from memory, so this remains just a build
test.

* run_tests/run_fp_tests: Print summary and give meaningful exit code

* run_tests/run_fp_tests: Include tests and failures in top-level XML entity

* run_tests/run_fp_tests: Use failure not error for XML output

The former is the standard tag for normal test failures, the latter is
for catastrophic things like test harness errors.

* Run ISA tests in CI

pull-requests ideally come with an explanation how the correctness of
the PR was established.

These are intended to deal with much of the low-hanging fruit; plenty of
room for improvement exists.

The order used for wildcard is not deterministic and varies between
systems. Sorting ensures the diffs are easy to inspect going forwards.

Closes: #142

NB: Smstateen support is missing in the model so enabling the Zfinx
extension provides an architectural covert channel via FCSR if
privileged software is not aware of Zfinx's existence.

Co-authored-by: Jessica Clarke <jrtc27@jrtc27.com>

Co-authored-by: Ibrahim Abu Kharmeh <abukharmeh@gmail.com>