Make digit_value a lookup table instead of a function

FlorenceOS · Aug 30, 2023 · cab2eaa · cab2eaa
1 parent 4d87818
commit cab2eaa
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Showing 2 changed files with 44 additions and 25 deletions.
diff --git a/selfhost/tokenizer.n b/selfhost/tokenizer.n
@@ -70,6 +70,7 @@ var token_offset: std.containers.PinnedVector(u32, MAX_TOKENS) = undefined;
 
 // TODO add array initializers
 var token_handlers: [256]Handler = undefined;
+var digit_value: [256]u8 = undefined;
 
 fn fill_handlers(start: u64, end: u64, handler: Handler) inline void {
     var curr_h = token_handlers[start].&;
@@ -105,6 +106,29 @@ fn init() void {
     token_handlers['@'] = ident_h;
     token_handlers['_'] = ident_h;
 
+    {
+        var ch: u32 = 0;
+        loop(ch <= 0xFF) {
+            digit_value[ch] = 0xFF;
+            ch += 1;
+        }
+        ch = '0';
+        loop(ch <= '9') {
+            digit_value[ch] = @truncate(u8, ch) - '0';
+            ch += 1;
+        }
+        ch = 'a';
+        loop(ch <= 'f') {
+            digit_value[ch] = @truncate(u8, ch) - 'a';
+            ch += 1;
+        }
+        ch = 'A';
+        loop(ch <= 'F') {
+            digit_value[ch] = @truncate(u8, ch) - 'A';
+            ch += 1;
+        }
+    }
+
     fill_handlers('0', '9' + 1, fn (context: *TokenizationContext, ch: u8) void {
         context.add_token(TokenType.int_literal);
         var base: u8 = 10;
@@ -119,7 +143,7 @@ fn init() void {
                 base = 2;
             }
         }
-        loop(digit_value(context.peek(0)) < base) {
+        loop(digit_value[context.peek(0)] < base) {
             context.advance(1);
         }
     }.&);
@@ -171,19 +195,6 @@ fn init() void {
     }.&;
 }
 
-fn digit_value(ch: u8) inline u8 {
-    if('0' <= ch && ch <= '9') {
-        return ch - '0' + 0x0;
-    }
-    if('a' <= ch && ch <= 'f') {
-        return ch - 'a' + 0xa;
-    }
-    if('A' <= ch && ch <= 'F') {
-        return ch - 'A' + 0xA;
-    }
-    return 0xFF;
-}
-
 fn badchar_handler(context: *TokenizationContext) void {
     context.report_error("Bad character".&);
 }

diff --git a/std/containers/pinned_vector.n b/std/containers/pinned_vector.n
@@ -23,6 +23,22 @@ const GenericVector = struct {
         self.committed_size = 0;
     }
 
+    fn deinit(self: *@This(), bytes: usize) void {
+        syscalls.munmap(
+            self.ptr,
+            bytes,
+        );
+    }
+
+    fn add(self: *@This()) u32 {
+        const retval = self.size;
+        self.size += 1;
+        if(self.size > self.committed_size) {
+            self.committed_size = self.size;
+        }
+        return retval;
+    }
+
     fn madvise(self: *const @This(), offset: u64, size: u64, advice: u32) inline void {
         syscalls.madvise(self.ptr + offset, size, advice);
     }
@@ -41,24 +57,16 @@ fn PinnedVector(comptime T: type, comptime capacity: u32) type {
         }
 
         fn deinit(self: *@This()) inline void {
-            syscalls.munmap(
-                self.gen.ptr,
-                @size_of(T) * capacity,
-            );
+            self.gen.deinit(@size_of(T) * capacity);
         }
 
         fn append_assume_capacity(self: *@This(), value: T) u32 {
             self.get(self.gen.size).* = value;
             return self.add();
         }
 
-        fn add(self: *@This()) u32 {
-            const retval = self.gen.size;
-            self.gen.size += 1;
-            if(self.gen.size > self.gen.committed_size) {
-                self.gen.committed_size = self.gen.size;
-            }
-            return retval;
+        fn add(self: *@This()) inline u32 {
+            return self.gen.add();
         }
 
         fn items_to_pages(items: u64) inline u64 {