[otbn] rename OTBN assembler Python script

In order to be bazelified, which is required in order to build the mask
ROM with bazel, all Python scripts must end in a ".py" extension.

Signed-off-by: Timothy Trippel <ttrippel@google.com>

doc/ug/otbn_sw.md

@@ -23,14 +23,14 @@ For specific formatting and secure coding guidelines, see the [OTBN style guide]
 
 ### Assembler
 
-The OTBN assembler is called `otbn-as` and can be found at `hw/ip/otbn/util/otbn-as`.
+The OTBN assembler is called `otbn_as.py` and can be found at `hw/ip/otbn/util/otbn_as.py`.
 This has the same command line interface as `riscv32-unknown-elf-as` (indeed, it's a wrapper around that program).
-The only difference in default flags is that `otbn-as` passes `-mno-relax`, telling the assembler not to request linker relaxation.
+The only difference in default flags is that `otbn_as.py` passes `-mno-relax`, telling the assembler not to request linker relaxation.
 This is needed because one of these relaxations generates GP-relative loads, which assume `x3` is treated as a global pointer (not true for OTBN code).
 
 To assemble some code in `foo.s` to an ELF object called `foo.o`, run:
 ```shell
-hw/ip/otbn/util/otbn-as -o foo.o foo.s
+hw/ip/otbn/util/otbn_as.py -o foo.o foo.s
 ```
 
 ### Linker

hw/ip/otbn/README.md

@@ -22,11 +22,11 @@ toolchain](https://docs.opentitan.org/doc/ug/install_instructions/#software-deve
 For more details about the toolchain, see the [user
 guide](https://docs.opentitan.org/doc/ug/otbn_sw)).
 
-`otbn-as` and `otbn_ld.py` can be used to build .elf files for use with
+`otbn_as.py` and `otbn_ld.py` can be used to build .elf files for use with
 simulations. They work work similarly to binutils programs they wrap.
 
 ```
-hw/ip/otbn/util/otbn-as -o prog_bin/prog.o prog.s
+hw/ip/otbn/util/otbn_as.py -o prog_bin/prog.o prog.s
 hw/ip/otbn/util/otbn_ld.py -o prog_bin/prog.elf prog_bin/prog.o
 ```
 
@@ -50,7 +50,7 @@ users include:
 ### Run the Python simulator
 The quickest way to run an OTBN-only program is to use the Python simulator.
 First, generate a `.elf.` file either using the usual build process or by
-manually running `otbn-as` and `otbn_ld.py` as shown above. Then, from `$REPO_TOP`:
+manually running `otbn_as.py` and `otbn_ld.py` as shown above. Then, from `$REPO_TOP`:
 ```console
 $ hw/ip/otbn/dv/otbnsim/standalone.py -t path/to/prog.elf
 ```

hw/ip/otbn/doc/_index.md

@@ -1109,7 +1109,7 @@ OTBN comes with a toolchain consisting of an assembler, a linker, and helper too
 The toolchain wraps a RV32 GCC toolchain and supports many of its features.
 
 The following tools are available:
-* `otbn-as`: The OTBN assembler.
+* `otbn_as.py`: The OTBN assembler.
 * `otbn_ld.py`: The OTBN linker.
 * `otbn-objdump`: objdump for OTBN.
 

hw/ip/otbn/dv/otbnsim/test/simple/insns/addi.s

@@ -6,7 +6,7 @@
     Simple tests of the addi instruction
 
     This test also uses a comment syntax that broke the parser in a
-    previous version of otbn-as: if editing it, keep the block
+    previous version of otbn_as.py: if editing it, keep the block
     comments on the same lines as instructions to keep that test in
     place.
 

hw/ip/otbn/dv/otbnsim/test/testutil.py

@@ -21,7 +21,7 @@ def asm_and_link_one_file(asm_path: str, work_dir: py.path.local) -> str:
     Returns the path to the resulting ELF
 
     '''
-    otbn_as = os.path.join(UTIL_DIR, 'otbn-as')
+    otbn_as = os.path.join(UTIL_DIR, 'otbn_as.py')
     otbn_ld = os.path.join(UTIL_DIR, 'otbn_ld.py')
     obj_path = os.path.join(work_dir, 'tst.o')
     elf_path = os.path.join(work_dir, 'tst')

hw/ip/otbn/dv/rig/README.md

@@ -86,7 +86,7 @@ are an assembly listing and a linker script, respectively.
 
 To assemble and link, use commands like:
 ```
-hw/ip/otbn/util/otbn-as -o foo.o foo.s
+hw/ip/otbn/util/otbn_as.py -o foo.o foo.s
 hw/ip/otbn/util/otbn_ld.py -o foo.elf -T foo.ld foo.o
 ```
 This is automated in the `gen-binaries.py` wrapper described above.

hw/ip/otbn/dv/smoke/run_smoke.sh

@@ -27,7 +27,7 @@ mkdir -p $SMOKE_BIN_DIR
 
 OTBN_UTIL=$REPO_TOP/hw/ip/otbn/util
 
-$OTBN_UTIL/otbn-as -o $SMOKE_BIN_DIR/smoke_test.o $SMOKE_SRC_DIR/smoke_test.s || \
+$OTBN_UTIL/otbn_as.py -o $SMOKE_BIN_DIR/smoke_test.o $SMOKE_SRC_DIR/smoke_test.s || \
     fail "Failed to assemble smoke_test.s"
 $OTBN_UTIL/otbn_ld.py -o $SMOKE_BIN_DIR/smoke.elf $SMOKE_BIN_DIR/smoke_test.o || \
     fail "Failed to link smoke_test.o"

hw/ip/otbn/util/Makefile

@@ -16,7 +16,7 @@ $(build-dir) $(lint-build-dir):
 	mkdir -p $@
 
 pylibs := $(wildcard shared/*.py docs/*.py)
-pyscripts := yaml_to_doc.py otbn-as otbn_ld.py otbn-objdump
+pyscripts := yaml_to_doc.py otbn_as.py otbn_ld.py otbn-objdump
 
 lint-stamps := $(foreach s,$(pyscripts),$(lint-build-dir)/$(s).stamp)
 $(lint-build-dir)/%.stamp: % $(pylibs) | $(lint-build-dir)