--- a/crates/jrsonnet-evaluator/src/builtin/mod.rs
+++ b/crates/jrsonnet-evaluator/src/builtin/mod.rs
@@ -97,6 +97,8 @@
 			("acos".into(), builtin_acos),
 			("atan".into(), builtin_atan),
 			("exp".into(), builtin_exp),
+			("mantissa".into(), builtin_mantissa),
+			("exponent".into(), builtin_exponent),
 			("extVar".into(), builtin_ext_var),
 			("native".into(), builtin_native),
 			("filter".into(), builtin_filter),
@@ -376,6 +378,33 @@
 	})
 }
 
+fn frexp(s: f64) -> (f64, i16) {
+	if 0.0 == s {
+		return (s, 0);
+	} else {
+		let lg = s.abs().log2();
+		let x = (lg - lg.floor() - 1.0).exp2();
+		let exp = lg.floor() + 1.0;
+		(s.signum() * x, exp as i16)
+	}
+}
+
+fn builtin_mantissa(context: Context, _loc: Option<&ExprLocation>, args: &ArgsDesc) -> Result<Val> {
+	parse_args!(context, "mantissa", args, 1, [
+		0, x: ty!(number) => Val::Num;
+	], {
+		Ok(Val::Num(frexp(x).0))
+	})
+}
+
+fn builtin_exponent(context: Context, _loc: Option<&ExprLocation>, args: &ArgsDesc) -> Result<Val> {
+	parse_args!(context, "exponent", args, 1, [
+		0, x: ty!(number) => Val::Num;
+	], {
+		Ok(Val::Num(frexp(x).1.into()))
+	})
+}
+
 fn builtin_ext_var(context: Context, _loc: Option<&ExprLocation>, args: &ArgsDesc) -> Result<Val> {
 	parse_args!(context, "extVar", args, 1, [
 		0, x: ty!(string) => Val::Str;
--- a/crates/jrsonnet-stdlib/src/std.jsonnet
+++ b/crates/jrsonnet-stdlib/src/std.jsonnet
@@ -35,6 +35,8 @@
   atan:: $intrinsic(atan),
 
   exp:: $intrinsic(exp),
+  mantissa:: $intrinsic(mantissa),
+  exponent:: $intrinsic(exponent),
 
   isString(v):: std.type(v) == 'string',
   isNumber(v):: std.type(v) == 'number',