duskos

commit f40f3e9f6ddb1c0d02bc29844dcd4cd9251d2820
parent 180bb94f0f1e24cffbb5772abd8b2261a874e804
Author: Virgil Dupras <hsoft@hardcoded.net>
Date:   Sat,  5 Nov 2022 13:29:25 -0400

cc: fold constant macro expressions when necessary

Diffstat:
M
fs/app/cos/cvm.c
 | 
3
+--
M
fs/cc/macro.fs
 | 
5
++---
M
fs/cc/ttr.fs
 | 
45
+++++++++++++++++++++++++++++----------------
M
fs/tests/cc/test.c
 | 
3
++-

4 files changed, 34 insertions(+), 22 deletions(-)
diff --git a/fs/app/cos/cvm.c b/fs/app/cos/cvm.c
@@ -4,8 +4,7 @@
 #define SP_ADDR $fffa
 #define RS_ADDR $ff00
 #define SYSVARS $fe00
-// TODO: allow constant expressions in macros to allow stuff like SYSVARS + $18
-#define SYSVARS_TOPTR $fe18
+#define SYSVARS_TOPTR SYSVARS+$18
 /* Port for block reads. Each read or write has to be done in 5 IO writes:
  * 1 - r/w. 1 for read, 2 for write.
  * 2 - blkid MSB
diff --git a/fs/cc/macro.fs b/fs/cc/macro.fs
@@ -1,14 +1,13 @@
 \ CC macros (high part)
 ?f<< /cc/macrolo.fs
 ?f<< /cc/ast.fs
+?f<< /cc/ttr.fs
 
 : _err ( -- ) abort" macro error" ;
 : _assert ( f -- ) not if _err then ;
 
 struct+[ Macro
-  : _asnum ( self -- n )
-    ast dup Node id AST_CONSTANT = _assert
-    Constant value ;
+  : _asnum ( self -- n ) ast ASTNode :?asnum _assert ;
   current to :asnum
 
 struct+[ MacroOps
diff --git a/fs/cc/ttr.fs b/fs/cc/ttr.fs
@@ -49,6 +49,33 @@ BOPSCNT wordtbl bopconsttbl ( -- )
 'w _err
 'w _err
 
+struct+[ ASTNode
+  \ Try to transform this node into a constant number.
+  \ f=1 and n=number if it's possible, otherwise f=0.
+  : :?asnum ( self -- n? f ) dup id case ( self )
+      AST_CONSTANT of = Constant value 1 endof
+      AST_UNARYOP of =
+        dup firstchild :?asnum if ( self n )
+          swap uopconsttbl swap UnaryOp opid wexec 1
+          else drop 0 then endof
+      AST_BINARYOP of =
+        dup firstchild dup :?asnum if ( self child n1 )
+          swap nextsibling :?asnum if ( self n1 n2 )
+            rot bopconsttbl swap BinaryOp opid wexec 1
+            else 2drop 0 then
+        else 2drop 0 then endof
+      drop 0
+    endcase ;
+]struct
+
+struct+[ Op
+  \ If possible, fold this node into a Constant.
+  : :?fold ( self -- )
+    dup >r :?asnum if
+      AST_CONSTANT to r@ id ( n ) to r@ Constant value 0 to r@ firstchild then
+    rdrop ;
+]struct
+
 alias noop trnode ( node -- ) \ forward declaration
 
 : trchildren ( node -- )
@@ -64,23 +91,9 @@ ASTIDCNT wordtbl trtbl ( node -- )
 'w trchildren ( Statements )
 'w _err ( unused )
 'w drop ( Ident )
-:w ( UnaryOp )
-  dup >r trchildren
-  r@ Node firstchild dup Node id AST_CONSTANT = if
-    Constant value uopconsttbl r@ UnaryOp opid wexec ( n )
-    AST_CONSTANT to r@ Node id ( n ) to r@ Constant value
-    0 to r@ Node firstchild else drop then
-  rdrop ;
+:w ( UnaryOp ) dup trchildren UnaryOp :?fold ;
 'w trchildren ( PostfixOp )
-:w ( BinaryOp )
-  dup >r BinaryOp :*ari r@ trchildren
-  r@ Node firstchild dup Node nextsibling ( n1 n2 )
-  over Node id AST_CONSTANT = over Node id AST_CONSTANT = and if
-    Constant value swap Constant value swap
-    bopconsttbl r@ BinaryOp opid wexec ( n )
-    AST_CONSTANT to r@ Node id ( n ) to r@ Constant value
-    0 to r@ Node firstchild else 2drop then
-  rdrop ;
+:w ( BinaryOp ) dup BinaryOp :*ari dup trchildren BinaryOp :?fold ;
 'w trchildren ( List )
 'w trchildren ( If )
 'w drop ( StrLit )
diff --git a/fs/tests/cc/test.c b/fs/tests/cc/test.c
@@ -1,6 +1,7 @@
 /* test a few simple C constructs */
 
-#define MYCONST 42
+#define FOUR 4
+#define MYCONST 40+FOUR-2
 
 // just return a constant
 short retconst() {