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| author | Clifford Wolf <clifford@clifford.at> | 2019-08-15 22:48:13 +0200 |
|---|---|---|
| committer | Clifford Wolf <clifford@clifford.at> | 2019-08-15 22:48:13 +0200 |
| commit | 969ab9027a8c4ee831e39f193f7ecb68457152c3 (patch) | |
| tree | f112c108762a9ab3a13add9d5e55bea11fcd81c9 | |
| parent | eb80d3d43fdb070fe99718501d3b0fbdca61ab8d (diff) | |
| download | yosys-969ab9027a8c4ee831e39f193f7ecb68457152c3.tar.gz yosys-969ab9027a8c4ee831e39f193f7ecb68457152c3.tar.bz2 yosys-969ab9027a8c4ee831e39f193f7ecb68457152c3.zip | |
Update pmgen documentation
Signed-off-by: Clifford Wolf <clifford@clifford.at>
| -rw-r--r-- | passes/pmgen/README.md | 62 |
1 files changed, 58 insertions, 4 deletions
diff --git a/passes/pmgen/README.md b/passes/pmgen/README.md index db722c818..4aa7de162 100644 --- a/passes/pmgen/README.md +++ b/passes/pmgen/README.md @@ -118,8 +118,8 @@ write matchers: connected to any of the given signal bits, plus one if any of the signal bits is also a primary input or primary output. -- In `code..endcode` blocks there exist `accept`, `reject`, and `branch` - statements. +- In `code..endcode` blocks there exist `accept`, `reject`, `branch`, and + `subpattern` statements. - In `index` statements there is a special `===` operator for the index lookup. @@ -233,7 +233,7 @@ But in some cases it is more natural to utilize the implicit branch statement: endcode There is an implicit `code..endcode` block at the end of each (sub)pattern -that just accepts everything that gets all the way there. +that just rejects. A `code..finally..endcode` block executes the code after `finally` during back-tracking. This is useful for maintaining user data state or printing @@ -243,10 +243,14 @@ debug messages. For example: code stack.push_back(addAB); + ... finally stack.pop_back(); endcode +`accept` statements can be used inside the `finally` section, but not +`reject`, `branch`, or `subpattern`. + Declaring a subpattern ---------------------- @@ -256,4 +260,54 @@ using a `subpattern(<subpattern_name>);` C statement. Arguments may be passed to subpattern via state variables. The `subpattern` line must be followed by a `arg <arg1> <arg2> ...` line that lists the -state variables used to pass arguments. Subpatterns allow recursion. +state variables used to pass arguments. + + state <IdString> foobar_type + state <bool> foobar_state + + code foobar_type foobar_state + foobar_state = false; + foobar_type = $add; + subpattern(foo); + foobar_type = $sub; + subpattern(bar); + endcode + + subpattern foo + arg foobar_type foobar_state + + match addsub + index <IdString> addsub->type === foobar_type + ... + endmatch + + code + if (foobar_state) { + subpattern(tail); + } else { + foobar_state = true; + subpattern(bar); + } + endcode + + subpattern bar + arg foobar_type foobar_state + + match addsub + index <IdString> addsub->type === foobar_type + ... + endmatch + + code + if (foobar_state) { + subpattern(tail); + } else { + foobar_state = true; + subpattern(foo); + } + endcode + + subpattern tail + ... + +Subpatterns cann be called recursively. |