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Diffstat (limited to 'docs/src/explanations/printing.md')
| -rw-r--r-- | docs/src/explanations/printing.md | 46 |
1 files changed, 28 insertions, 18 deletions
diff --git a/docs/src/explanations/printing.md b/docs/src/explanations/printing.md index abd1a427..80e9ec70 100644 --- a/docs/src/explanations/printing.md +++ b/docs/src/explanations/printing.md @@ -13,22 +13,34 @@ Chisel provides the `printf` function for debugging purposes. It comes in two fl ### Scala-style -Chisel also supports printf in a style similar to [Scala's String Interpolation](http://docs.scala-lang.org/overviews/core/string-interpolation.html). Chisel provides a custom string interpolator `p` which can be used as follows: +Chisel also supports printf in a style similar to [Scala's String Interpolation](http://docs.scala-lang.org/overviews/core/string-interpolation.html). Chisel provides a custom string interpolator `cf` which follows C-style format specifiers (see section [C-style](#c-style) below). + +Note that the Scala s-interpolator is not supported in Chisel constructs and will issue a compile-time warning: ```scala mdoc:invisible import chisel3._ ``` + +```scala mdoc:warn +class MyModule extends Module { + val in = IO(Input(UInt(8.W))) + printf(s"in = $in\n") +} +``` + +Instead, use Chisel's `cf` interpolator as in the following examples: + ```scala mdoc:compile-only val myUInt = 33.U -printf(p"myUInt = $myUInt") // myUInt = 33 +printf(cf"myUInt = $myUInt") // myUInt = 33 ``` -Note that when concatenating `p"..."` strings, you need to start with a `p"..."` string: +Note that when concatenating `cf"..."` strings, you need to start with a `cf"..."` string: ```scala mdoc:compile-only // Does not interpolate the second string val myUInt = 33.U -printf("my normal string" + p"myUInt = $myUInt") +printf("my normal string" + cf"myUInt = $myUInt") ``` #### Simple formatting @@ -38,22 +50,20 @@ Other formats are available as follows: ```scala mdoc:compile-only val myUInt = 33.U // Hexadecimal -printf(p"myUInt = 0x${Hexadecimal(myUInt)}") // myUInt = 0x21 +printf(cf"myUInt = 0x$myUInt%x") // myUInt = 0x21 // Binary -printf(p"myUInt = ${Binary(myUInt)}") // myUInt = 100001 +printf(cf"myUInt = $myUInt%b") // myUInt = 100001 // Character -printf(p"myUInt = ${Character(myUInt)}") // myUInt = ! +printf(cf"myUInt = $myUInt%c") // myUInt = ! ``` -We recognize that the format specifiers are verbose, so we are working on a more concise syntax. - #### Aggregate data-types Chisel provides default custom "pretty-printing" for Vecs and Bundles. The default printing of a Vec is similar to printing a Seq or List in Scala while printing a Bundle is similar to printing a Scala Map. ```scala mdoc:compile-only val myVec = VecInit(5.U, 10.U, 13.U) -printf(p"myVec = $myVec") // myVec = Vec(5, 10, 13) +printf(cf"myVec = $myVec") // myVec = Vec(5, 10, 13) val myBundle = Wire(new Bundle { val foo = UInt() @@ -61,7 +71,7 @@ val myBundle = Wire(new Bundle { }) myBundle.foo := 3.U myBundle.bar := 11.U -printf(p"myBundle = $myBundle") // myBundle = Bundle(a -> 3, b -> 11) +printf(cf"myBundle = $myBundle") // myBundle = Bundle(a -> 3, b -> 11) ``` #### Custom Printing @@ -76,11 +86,11 @@ class Message extends Bundle { val data = UInt(64.W) override def toPrintable: Printable = { val char = Mux(valid, 'v'.U, '-'.U) - p"Message:\n" + - p" valid : ${Character(char)}\n" + - p" addr : 0x${Hexadecimal(addr)}\n" + - p" length : $length\n" + - p" data : 0x${Hexadecimal(data)}\n" + cf"Message:\n" + + cf" valid : $char%c\n" + + cf" addr : $addr%x\n" + + cf" length : $length\n" + + cf" data : $data%x\n" } } @@ -90,7 +100,7 @@ myMessage.addr := "h1234".U myMessage.length := 10.U myMessage.data := "hdeadbeef".U -printf(p"$myMessage") +printf(cf"$myMessage") ``` Which prints the following: @@ -103,7 +113,7 @@ Message: data : 0x00000000deadbeef ``` -Notice the use of `+` between `p` interpolated "strings". The results of `p` interpolation can be concatenated by using the `+` operator. For more information, please see the documentation +Notice the use of `+` between `cf` interpolated "strings". The results of `cf` interpolation can be concatenated by using the `+` operator. ### C-Style |
