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Add support for the Zfa ISA extension #60

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May 3, 2024

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This patch introduces the RISC-V Zfa extension, which introduces additional floating-point extensions:

  • fli (load-immediate) with pre-defined immediates
  • fminm/fmaxm (like fmin/fmax but with different NaN behaviour)
  • fround/froundmx (round to integer)
  • fcvtmod.w.d (Modular Convert-to-Integer)
  • fmv* to access high bits of float register bigger than XLEN
  • Quiet comparison instructions (fleq/fltq)

Zfa defines its instructions in combination with the following extensions:

  • single-precision floating-point (F)
  • double-precision floating-point (D)
  • quad-precision floating-point (Q)
  • half-precision floating-point (Zfh)

Since riscv-ctg does not support the RISC-V quad-precision floating-point ISA extension (Q) as well as the RISC-V half-precision floating-point ISA extension (Zfh), this patch does not include the instructions that depend on these extensions. All other instructions are included in this patch.

The instruction descriptions (simple_cgfs/zfa/*) use different instructions as parameter for the coverpoint generator functions (e.g. fleq.s uses "fle.s") to circumvent documented limitations of these generator functions.

Technically there is no reason to adjust generator.py. All required information could be extracted from instruction descriptions. However, that is not the case, and the file also includes its own hard-coded assumptions, which have to be adjusted as well.

The Zfa specification can be found here:
https://github.com/riscv/riscv-isa-manual/blob/master/src/zfa.tex

cmuellner added a commit to cmuellner/riscv-arch-test that referenced this pull request Apr 6, 2023
This patch introduces the RISC-V Zfa extension, which introduces
additional floating-point extensions:
* fli (load-immediate) with pre-defined immediates
* fminm/fmaxm (like fmin/fmax but with different NaN behaviour)
* fround/froundmx (round to integer)
* fcvtmod.w.d (Modular Convert-to-Integer)
* fmv* to access high bits of float register bigger than XLEN
* Quiet comparison instructions (fleq/fltq)

Zfa defines its instructions in combination with the following
extensions:
* single-precision floating-point (F)
* double-precision floating-point (D)
* quad-precision floating-point (Q)
* half-precision floating-point (Zfh)

Since the RISC-V architecture test framework does not support
the RISC-V quad-precision floating-point ISA extension (Q) and
the RISC-V half-precision floating-point ISA extension (Zfh),
this patch does not include tests for instructions that depend
on these extensions.

Given missing infrastructure support, the fli.* instruction tests
are hand written and not generated.
All other test files are generated using riscv-ctg.

The generated test files have been generated using the following
command (with $BASEISA={rv32i,rv64i} and $FLEN={32,64}):
      riscv_ctg.py \
        --cgf coverage/dataset.cgf \
        --cgf coverage/zicond.cgf \
        --base-isa $BASEISA \
        --flen $FLEN \
        -d tests_$BASEISA_$FLEN/

Exceptions are:
* fcvtmod.w.d.cgf is for FLEN=32 only
* fmvh.x.d and fmvp.d.x are for BASEISA=rv32i only

The resulting tests have been copied to the target directory.

The generation of the Zfa test cases depends on a PR in the riscv-ctg
repository:
  riscv-software-src/riscv-ctg#60

The Zfa specification is not frozen at the moment (which is why this
patch is RFC) and can be found here:
https://github.com/riscv/riscv-isa-manual/blob/master/src/zfa.tex

Signed-off-by: Christoph Müllner <[email protected]>
cmuellner added a commit to cmuellner/riscv-arch-test that referenced this pull request May 10, 2023
This patch introduces the RISC-V Zfa extension, which introduces
additional floating-point extensions:
* fli (load-immediate) with pre-defined immediates
* fminm/fmaxm (like fmin/fmax but with different NaN behaviour)
* fround/froundmx (round to integer)
* fcvtmod.w.d (Modular Convert-to-Integer)
* fmv* to access high bits of float register bigger than XLEN
* Quiet comparison instructions (fleq/fltq)

Zfa defines its instructions in combination with the following
extensions:
* single-precision floating-point (F)
* double-precision floating-point (D)
* quad-precision floating-point (Q)
* half-precision floating-point (Zfh)

Since the RISC-V architecture test framework does not support
the RISC-V quad-precision floating-point ISA extension (Q) and
the RISC-V half-precision floating-point ISA extension (Zfh),
this patch does not include tests for instructions that depend
on these extensions.

Given missing infrastructure support, the fli.* instruction tests
are hand written and not generated.
All other test files are generated using riscv-ctg.

The generated test files have been generated using the following
command (with $BASEISA={rv32i,rv64i} and $FLEN={32,64}):
      riscv_ctg.py \
        --cgf coverage/dataset.cgf \
        --cgf coverage/zicond.cgf \
        --base-isa $BASEISA \
        --flen $FLEN \
        -d tests_$BASEISA_$FLEN/

Exceptions are:
* fcvtmod.w.d.cgf is for FLEN=32 only
* fmvh.x.d and fmvp.d.x are for BASEISA=rv32i only

The resulting tests have been copied to the target directory.

The generation of the Zfa test cases depends on a PR in the riscv-ctg
repository:
  riscv-software-src/riscv-ctg#60

The Zfa specification is not frozen at the moment (which is why this
patch is RFC) and can be found here:
https://github.com/riscv/riscv-isa-manual/blob/master/src/zfa.tex

Signed-off-by: Christoph Müllner <[email protected]>
@cmuellner cmuellner force-pushed the zfa branch 2 times, most recently from 0aabb82 to 99d3b40 Compare May 23, 2023 09:56
@cmuellner
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Updated PR:

  • rebased
  • updated version to 0.11.1
  • updating all version copies
  • fcvtmod: Restrict rounding mode to 'rtz'

cmuellner added a commit to cmuellner/riscv-arch-test that referenced this pull request May 23, 2023
This patch introduces the RISC-V Zfa extension, which introduces
additional floating-point extensions:
* fli (load-immediate) with pre-defined immediates
* fminm/fmaxm (like fmin/fmax but with different NaN behaviour)
* fround/froundmx (round to integer)
* fcvtmod.w.d (Modular Convert-to-Integer)
* fmv* to access high bits of float register bigger than XLEN
* Quiet comparison instructions (fleq/fltq)

Zfa defines its instructions in combination with the following
extensions:
* single-precision floating-point (F)
* double-precision floating-point (D)
* quad-precision floating-point (Q)
* half-precision floating-point (Zfh)

Since the RISC-V architecture test framework does not support
the RISC-V quad-precision floating-point ISA extension (Q) and
the RISC-V half-precision floating-point ISA extension (Zfh),
this patch does not include tests for instructions that depend
on these extensions.

Given missing infrastructure support, the fli.* instruction tests
are hand written and not generated.
All other test files are generated using riscv-ctg.

The generated test files have been generated using the following
command (with $BASEISA={rv32i,rv64i} and $FLEN={32,64}):
      riscv_ctg.py \
        --cgf coverage/dataset.cgf \
        --cgf coverage/zicond.cgf \
        --base-isa $BASEISA \
        --flen $FLEN \
        -d tests_$BASEISA_$FLEN/

Exceptions are:
* fcvtmod.w.d.cgf is for FLEN=32 only
* fmvh.x.d and fmvp.d.x are for BASEISA=rv32i only

The resulting tests have been copied to the target directory.

The generation of the Zfa test cases depends on a PR in the riscv-ctg
repository:
  riscv-software-src/riscv-ctg#60

The Zfa specification is not frozen at the moment (which is why this
patch is RFC) and can be found here:
https://github.com/riscv/riscv-isa-manual/blob/master/src/zfa.tex

Signed-off-by: Christoph Müllner <[email protected]>
cmuellner added a commit to cmuellner/riscv-arch-test that referenced this pull request May 23, 2023
This patch introduces the RISC-V Zfa extension, which introduces
additional floating-point extensions:
* fli (load-immediate) with pre-defined immediates
* fminm/fmaxm (like fmin/fmax but with different NaN behaviour)
* fround/froundmx (round to integer)
* fcvtmod.w.d (Modular Convert-to-Integer)
* fmv* to access high bits of float register bigger than XLEN
* Quiet comparison instructions (fleq/fltq)

Zfa defines its instructions in combination with the following
extensions:
* single-precision floating-point (F)
* double-precision floating-point (D)
* quad-precision floating-point (Q)
* half-precision floating-point (Zfh)

Since the RISC-V architecture test framework does not support
the RISC-V quad-precision floating-point ISA extension (Q) and
the RISC-V half-precision floating-point ISA extension (Zfh),
this patch does not include tests for instructions that depend
on these extensions.

Given missing infrastructure support, the fli.* instruction tests
are hand written and not generated.
All other test files are generated using riscv-ctg.

The generated test files have been generated using the following
command (with $BASEISA={rv32i,rv64i} and $FLEN={32,64}):
      riscv_ctg.py \
        --cgf coverage/dataset.cgf \
        --cgf coverage/zicond.cgf \
        --base-isa $BASEISA \
        --flen $FLEN \
        -d tests_$BASEISA_$FLEN/

Exceptions are:
* fcvtmod.w.d.cgf is for FLEN=32 only
* fmvh.x.d and fmvp.d.x are for BASEISA=rv32i only

The resulting tests have been copied to the target directory.

The generation of the Zfa test cases depends on a PR in the riscv-ctg
repository:
  riscv-software-src/riscv-ctg#60

The Zfa specification is not frozen at the moment (which is why this
patch is RFC) and can be found here:
https://github.com/riscv/riscv-isa-manual/blob/master/src/zfa.tex

Signed-off-by: Christoph Müllner <[email protected]>
@jamesbeyond
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@cmuellner could you try rebase this PR again, we think the issue riscv-non-isa/riscv-arch-test#331 got fixed already. please use latest riscv-arch-test repo

@cmuellner
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I've rebased the PR.

cmuellner added a commit to cmuellner/riscv-arch-test that referenced this pull request Jan 16, 2024
This patch introduces the RISC-V Zfa extension, which introduces
additional floating-point extensions:
* fli (load-immediate) with pre-defined immediates
* fminm/fmaxm (like fmin/fmax but with different NaN behaviour)
* fround/froundmx (round to integer)
* fcvtmod.w.d (Modular Convert-to-Integer)
* fmv* to access high bits of float register bigger than XLEN
* Quiet comparison instructions (fleq/fltq)

Zfa defines its instructions in combination with the following
extensions:
* single-precision floating-point (F)
* double-precision floating-point (D)
* quad-precision floating-point (Q)
* half-precision floating-point (Zfh)

Since the RISC-V architecture test framework does not support
the RISC-V quad-precision floating-point ISA extension (Q) and
the RISC-V half-precision floating-point ISA extension (Zfh),
this patch does not include tests for instructions that depend
on these extensions.

Given missing infrastructure support, the fli.* instruction tests
are hand written and not generated.
All other test files are generated using riscv-ctg.

The generated test files have been generated using the following
command (with $BASEISA={rv32i,rv64i} and $FLEN={32,64}):
      riscv_ctg.py \
        --cgf coverage/dataset.cgf \
        --cgf coverage/zicond.cgf \
        --base-isa $BASEISA \
        --flen $FLEN \
        -d tests_$BASEISA_$FLEN/

Exceptions are:
* fcvtmod.w.d.cgf is for FLEN=32 only
* fmvh.x.d and fmvp.d.x are for BASEISA=rv32i only

The resulting tests have been copied to the target directory.

The generation of the Zfa test cases depends on a PR in the riscv-ctg
repository:
  riscv-software-src/riscv-ctg#60

The Zfa specification is not frozen at the moment (which is why this
patch is RFC) and can be found here:
https://github.com/riscv/riscv-isa-manual/blob/master/src/zfa.tex

Signed-off-by: Christoph Müllner <[email protected]>
@cmuellner
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I've rebased the PR and addressed an issue with the generation of tests for the froundnx instruction.

The recently introduced toint() function does not accept arguments
of type int and will trigger an exception in this case.
This leads to an always crashing code path in generator.py,
where rm_dict[] maps the rounding mode string to an integer,
that is then passed to toint().

There are several ways to address this (e.g. mapping to a string,
or making toint() more robust), but dropping the call to toint()
is obviously the right thing to do.

Signed-off-by: Christoph Müllner <[email protected]>
This patch introduces the RISC-V Zfa extension, which introduces
additional floating-point extensions:
* fli (load-immediate) with pre-defined immediates
* fminm/fmaxm (like fmin/fmax but with different NaN behaviour)
* fround/froundmx (round to integer)
* fcvtmod.w.d (Modular Convert-to-Integer)
* fmv* to access high bits of float register bigger than XLEN
* Quiet comparison instructions (fleq/fltq)

Zfa defines its instructions in combination with the following
extensions:
* single-precision floating-point (F)
* double-precision floating-point (D)
* quad-precision floating-point (Q)
* half-precision floating-point (Zfh)

Since riscv-ctg does not support the RISC-V quad-precision floating-point
ISA extension (Q) as well as the RISC-V half-precision floating-point
ISA extension (Zfh), this patch does not include the instructions that
depend on these extensions. All other instructions are included in
this patch.

The instruction descriptions (simple_cgfs/zfa/*) use different
instructions as parameter for the coverpoint generator functions
(e.g. fleq.s uses "fle.s") to circumvent documented limitations
of these generator functions.

Technically there is no reason to adjust generator.py.
All required information could be extracted from instruction
descriptions. However, that is not the case, and the file
also includes its own hard-coded assumptions, which have
to be adjusted as well.

The Zfa specification can be found here:
  https://github.com/riscv/riscv-isa-manual/blob/master/src/zfa.tex

Signed-off-by: Christoph Müllner <[email protected]>
There is not much infrastucture support for the fli* instructions.
Let's add a cgf that defines the instruction's covergroup with the
existing infrastructure support.

Signed-off-by: Christoph Müllner <[email protected]>
The specification of fcvtmod requires a rounding mode of 'rtz'.
Let's restrict the generated test cases accordingly.

Signed-off-by: Christoph Müllner <[email protected]>
This fixes a typo in the mnemonics name which prevents the creation
of froundnx test cases.

Signed-off-by: Christoph Müllner <[email protected]>
A typo in the instruction definition prevented the creation of
fmvp.d.x test cases. Let's fix that.

Signed-off-by: Christoph Müllner <[email protected]>
The specification of fcvtmod requires a rounding mode of 'rtz'.
Recently we have added a commit to restrict the rounding modes
accoringly. However, that turned out to be unsufficient.
Therefore, this patch directly sets the rounding mode to 'rtz'.
As a result this patch only generates 'rtz' test cases.

Signed-off-by: Christoph Müllner <[email protected]>
@cmuellner
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Updated PR: Added a commit to make the rtz-only restriction more reliable for fcvtmod tests.

cmuellner added a commit to cmuellner/riscv-arch-test that referenced this pull request Apr 2, 2024
This patch introduces the RISC-V Zfa extension, which introduces
additional floating-point extensions:
* fli (load-immediate) with pre-defined immediates
* fminm/fmaxm (like fmin/fmax but with different NaN behaviour)
* fround/froundmx (round to integer)
* fcvtmod.w.d (Modular Convert-to-Integer)
* fmv* to access high bits of float register bigger than XLEN
* Quiet comparison instructions (fleq/fltq)

Zfa defines its instructions in combination with the following
extensions:
* single-precision floating-point (F)
* double-precision floating-point (D)
* quad-precision floating-point (Q)
* half-precision floating-point (Zfh)

Since the RISC-V architecture test framework does not support
the RISC-V quad-precision floating-point ISA extension (Q) and
the RISC-V half-precision floating-point ISA extension (Zfh),
this patch does not include tests for instructions that depend
on these extensions.

Given missing infrastructure support, the fli.* instruction tests
are hand written and not generated.
All other test files are generated using riscv-ctg.

The generated test files have been generated using the following
command (with $BASEISA={rv32i,rv64i}, $FLEN={32,64}), and CFG=$INSN:
      riscv_ctg.py \
        --cgf sample_cgfs/dataset.cgf \
        --cgf sample_cgfs/zfa/$CGF \
        --base-isa $BASEISA \
        --flen $FLEN \
        -d tests_$BASEISA_$FLEN/

Exceptions are:
* fcvtmod.w.d.cgf is for FLEN=32 only
* fmvh.x.d and fmvp.d.x are for BASEISA=rv32i only

The resulting tests have been copied to the target directory.

The generation of the Zfa test cases depends on a PR in the riscv-ctg
repository:
  riscv-software-src/riscv-ctg#60

The Zfa specification is ratified and can be found here:
  https://github.com/riscv/riscv-isa-manual/blob/main/src/zfa.adoc

Signed-off-by: Christoph Müllner <[email protected]>
Bump the CTG version to 0.12.2.

Signed-off-by: Christoph Müllner <[email protected]>
@cmuellner
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Updated riscv_ctg/__init__.py to match the version in CHANGELOG.md (to address the CI error).

@jamesbeyond
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@UmerShahidengr could you review this PR

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It looks fine to me. We can merge it straightaway

@UmerShahidengr UmerShahidengr merged commit 0b97b3d into riscv-software-src:master May 3, 2024
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@UmerShahidengr UmerShahidengr mentioned this pull request Jul 18, 2024
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3 participants