diff --git a/lib/bigint.c b/lib/bigint.c
index beef8ad..255cb79 100644
--- a/lib/bigint.c
+++ b/lib/bigint.c
@@ -3952,6 +3952,62 @@ oops_einval:
 	return HCL_NULL;
 }
 
+hcl_oop_t hcl_sqrtint (hcl_t* hcl, hcl_oop_t x)
+{
+	/* TODO: find a faster and more efficient algorithm??? */
+	hcl_oop_t a, b, m, m2, t;
+	
+	a = hcl->_nil;
+	b = hcl->_nil;
+	m = hcl->_nil;
+	m2 = hcl->_nil;
+
+	hcl_pushtmp (hcl, &x);
+	hcl_pushtmp (hcl, &a);
+	hcl_pushtmp (hcl, &b);
+	hcl_pushtmp (hcl, &m);
+	hcl_pushtmp (hcl, &m2);
+	
+	a = HCL_SMOOI_TO_OOP(1);
+	b = hcl_bitshiftint(hcl, x, HCL_SMOOI_TO_OOP(-5));
+	if (!b) goto oops;
+	b = hcl_addints(hcl, b, HCL_SMOOI_TO_OOP(8));
+	if (!b) goto oops;
+
+	while (1)
+	{
+		t = hcl_geints(hcl, b, a);
+		if (!t) return HCL_NULL;
+		if (t == hcl->_false) break;
+
+		m = hcl_addints(hcl, a, b);
+		if (!m) goto oops;
+		m = hcl_bitshiftint(hcl, m, HCL_SMOOI_TO_OOP(-1));
+		if (!m) goto oops;
+		m2 = hcl_mulints(hcl, m, m);
+		if (!m2) goto oops;
+		t = hcl_gtints(hcl, m2, x);
+		if (!t) return HCL_NULL;
+		if (t == hcl->_true)
+		{
+			b = hcl_subints(hcl, m, HCL_SMOOI_TO_OOP(1));
+			if (!b) goto oops;
+		}
+		else
+		{
+			a = hcl_addints(hcl, m, HCL_SMOOI_TO_OOP(1));
+			if (!a) goto oops;
+		}
+	}
+
+	hcl_poptmps (hcl, 5);
+	return hcl_subints(hcl, a, HCL_SMOOI_TO_OOP(1));
+
+oops:
+	hcl_poptmps (hcl, 5);
+	return HCL_NULL;
+}
+
 hcl_oop_t hcl_inttostr (hcl_t* hcl, hcl_oop_t num, int radix, int ngc)
 {
 	hcl_ooi_t v = 0;
diff --git a/lib/hcl-prv.h b/lib/hcl-prv.h
index 92672d6..2cdbef9 100644
--- a/lib/hcl-prv.h
+++ b/lib/hcl-prv.h
@@ -940,6 +940,11 @@ hcl_oop_t hcl_leints (
 	hcl_oop_t y
 );
 
+hcl_oop_t hcl_sqrtint (
+	hcl_t*    hcl,
+	hcl_oop_t x
+);
+
 hcl_oop_t hcl_strtoint (
 	hcl_t*            hcl,
 	const hcl_ooch_t* str,
@@ -1038,6 +1043,13 @@ hcl_oop_t hcl_nenums (
 	hcl_oop_t    x,
 	hcl_oop_t    y
 );
+
+hcl_oop_t hcl_sqrtnum (
+	hcl_t*       hcl,
+	hcl_oop_t    x
+);
+
+
 /* ========================================================================= */
 /* comp.c                                                                    */
 /* ========================================================================= */
diff --git a/lib/number.c b/lib/number.c
index e8575e9..b9b5448 100644
--- a/lib/number.c
+++ b/lib/number.c
@@ -335,7 +335,6 @@ hcl_oop_t hcl_lenums (hcl_t* hcl, hcl_oop_t x, hcl_oop_t y)
 	return comp_nums(hcl, x, y, hcl_leints);
 }
 
-
 hcl_oop_t hcl_eqnums (hcl_t* hcl, hcl_oop_t x, hcl_oop_t y)
 {
 	return comp_nums(hcl, x, y, hcl_eqints);
@@ -344,3 +343,25 @@ hcl_oop_t hcl_nenums (hcl_t* hcl, hcl_oop_t x, hcl_oop_t y)
 {
 	return comp_nums(hcl, x, y, hcl_neints);
 }
+
+hcl_oop_t hcl_sqrtnum (hcl_t* hcl, hcl_oop_t x)
+{
+	if (!HCL_IS_FPDEC(hcl, x))
+	{
+		return hcl_sqrtint(hcl, x);
+	}
+	else
+	{
+		/* TODO: debug this part... this part is buggy. not complete yet */
+		hcl_oop_t v;
+		hcl_ooi_t scale;
+		
+		scale = HCL_OOP_TO_SMOOI(((hcl_oop_fpdec_t)x)->scale);
+		v = ((hcl_oop_fpdec_t)x)->value;
+
+		v = hcl_sqrtint(hcl, v);
+		if (!v) return HCL_NULL;
+
+		return hcl_makefpdec(hcl, v, scale / 2);
+	}
+}
diff --git a/lib/prim.c b/lib/prim.c
index 87e6f28..6c4e048 100644
--- a/lib/prim.c
+++ b/lib/prim.c
@@ -499,6 +499,16 @@ static hcl_pfrc_t pf_number_rem (hcl_t* hcl, hcl_mod_t* mod, hcl_ooi_t nargs)
 	return HCL_PF_SUCCESS;
 }
 
+static hcl_pfrc_t pf_number_sqrt (hcl_t* hcl, hcl_mod_t* mod, hcl_ooi_t nargs)
+{
+	hcl_oop_t ret;
+	ret = hcl_sqrtnum(hcl, HCL_STACK_GETARG(hcl, nargs, 0)); /*TODO: change to hcl_sqrtnum()*/
+	if (!ret) return HCL_PF_FAILURE;
+
+	HCL_STACK_SETRET (hcl, nargs, ret);
+	return HCL_PF_SUCCESS;
+}
+
 static hcl_pfrc_t pf_number_gt (hcl_t* hcl, hcl_mod_t* mod, hcl_ooi_t nargs)
 {
 	hcl_oop_t ret;
@@ -585,6 +595,7 @@ static pf_t builtin_prims[] =
 	{ 1, HCL_TYPE_MAX(hcl_oow_t), pf_number_div,    1,  { '/' } },
 	{ 1, HCL_TYPE_MAX(hcl_oow_t), pf_number_quo,    3,  { 'q','u','o' } },
 	{ 2, HCL_TYPE_MAX(hcl_oow_t), pf_number_rem,    3,  { 'm','o','d' } },
+	{ 1, 1,                       pf_number_sqrt,   4,  { 's','q','r','t' } },
 
 	{ 2, 2,                       pf_number_gt,     1,  { '>' } },
 	{ 2, 2,                       pf_number_ge,     2,  { '>','=' } },