Make pretty printer stricter with brace placement

Also add a special case for shift-left when we are shifting 8 by a two
bit opcode, or 32 by a one bit opcode.

1 files changed, 19 insertions, 1 deletions

diff --git a/lib/arith.sail b/lib/arith.sail
index 61a1ff76..e61ec473 100644
--- a/lib/arith.sail
+++ b/lib/arith.sail
@@ -50,7 +50,25 @@ val "prerr_int" : (string, int) -> unit
 
 // ***** Integer shifts *****
 
-val shl_int = "shl_int" : (int, int) -> int
+/*!
+A common idiom in asl is to take two bits of an opcode and convert in into a variable like
+```
+let elsize = shl_int(8, UInt(size))
+```
+THIS ensures that in this case the typechecker knows that the end result will be a value in the set `{8, 16, 32, 64}`
+*/
+val _shl8 = "shl_int" :
+  forall 'n, 0 <= 'n <= 3. (int(8), int('n)) -> int('m) with 'm in {8, 16, 32, 64}
+
+/*!
+Similarly, we can shift 32 by either 0 or 1 to get a value in `{32, 64}`
+*/
+val _shl32 = "shl_int" :
+  forall 'n, 'n in {0, 1}. (int(32), int('n)) -> int('m) with 'm in {32, 64}
+
+val _shl_int = "shl_int" : (int, int) -> int
+
+overload shl_int = {_shl8, _shl32, _shl_int}
 
 val shr_int = "shr_int" : (int, int) -> int