diff --git a/src/expression/numberParser.test.ts b/src/expression/numberParser.test.ts
index 5016103..87cc3e4 100644
--- a/src/expression/numberParser.test.ts
+++ b/src/expression/numberParser.test.ts
@@ -101,4 +101,24 @@ describe("parser", () => {
         expect(typeof v?.value).toBe("bigint");
         expect(v?.value.toString()).toBe("1");
     });
+
+    xit('parses single', () => {
+        var v =  numberParser.parse('1s')?.value
+        expect(typeof v?.value).toBe("number");
+        expect(v?.maxBitSize).toBe(16);
+        expect(v?.value.toString()).toBe("1");
+
+        var v2 =  numberParser.parse('1i8')?.value
+        expect(v2).toEqual(v);
+    });
+
+    xit('parses byte', () => {
+        var v =  numberParser.parse('1b')?.value
+        expect(typeof v?.value).toBe("number");
+        expect(v?.maxBitSize).toBe(16);
+        expect(v?.value.toString()).toBe("1");
+
+        var v2 =  numberParser.parse('1i16')?.value
+        expect(v2).toEqual(v);
+    });
 });
\ No newline at end of file
diff --git a/src/expression/numberParser.ts b/src/expression/numberParser.ts
index e88b5c7..ed16998 100644
--- a/src/expression/numberParser.ts
+++ b/src/expression/numberParser.ts
@@ -5,9 +5,9 @@ import { BoundedNumber, asBoundedNumber } from "../core/types";
 // byte -i8 or b
 // single - i16 or s 
 
-const decimalRegex = /^-?\d+[l,L,S,s,B,b]?$/;
-const hexRegex = /^-?0x[0-9,a-f]+[l,L,S,s,B,b]?$/i;
-const binRegex = /^-?0b[0-1]+[l,L,S,s,B,b]?$/i;
+const decimalRegex = /^-?\d+[l,L]?$/;
+const hexRegex = /^-?0x[0-9,a-f]+[l,L]?$/i;
+const binRegex = /^-?0b[0-1]+[l,L]?$/i;
 
 interface ParserConfig {
     regex: RegExp,