diff --git a/builder/picolibc.go b/builder/picolibc.go
index 91ad27be..ab49ba5a 100644
--- a/builder/picolibc.go
+++ b/builder/picolibc.go
@@ -337,6 +337,12 @@ var picolibcSourcesLarge = []string{
 	"libm/common/math_err_may_uflow.c",
 	"libm/common/math_err_check_uflow.c",
 	"libm/common/math_err_check_oflow.c",
+	"libm/common/math_errf_divzerof.c",
+	"libm/common/math_errf_invalidf.c",
+	"libm/common/math_errf_may_uflowf.c",
+	"libm/common/math_errf_oflowf.c",
+	"libm/common/math_errf_uflowf.c",
+	"libm/common/math_errf_with_errnof.c",
 	"libm/common/math_inexact.c",
 	"libm/common/math_inexactf.c",
 	"libm/common/log.c",
diff --git a/testdata/math.go b/testdata/math.go
index eceb39f3..58b19096 100644
--- a/testdata/math.go
+++ b/testdata/math.go
@@ -39,6 +39,7 @@ func main() {
 		println("  remainder:", math.Remainder(n, n+0.2))
 		println("  sin:      ", math.Sin(n))
 		println("  sinh:     ", math.Sinh(n))
+		println("  sqrt:     ", float32(math.Sqrt(float64(n))))
 		println("  tan:      ", math.Tan(n))
 		println("  tanh:     ", math.Tanh(n))
 		println("  trunc:    ", math.Trunc(n))
diff --git a/testdata/math.txt b/testdata/math.txt
index 473ca4fe..8c8da627 100644
--- a/testdata/math.txt
+++ b/testdata/math.txt
@@ -31,6 +31,7 @@ n: +3.000000e-001
   remainder: -2.000000e-001
   sin:       +2.955202e-001
   sinh:      +3.045203e-001
+  sqrt:      +5.477226e-001
   tan:       +3.093362e-001
   tanh:      +2.913126e-001
   trunc:     +0.000000e+000
@@ -67,6 +68,7 @@ n: +1.500000e+000
   remainder: -2.000000e-001
   sin:       +9.974950e-001
   sinh:      +2.129279e+000
+  sqrt:      +1.224745e+000
   tan:       +1.410142e+001
   tanh:      +9.051483e-001
   trunc:     +1.000000e+000
@@ -103,6 +105,7 @@ n: +2.600000e+000
   remainder: -2.000000e-001
   sin:       +5.155014e-001
   sinh:      +6.694732e+000
+  sqrt:      +1.612452e+000
   tan:       -6.015966e-001
   tanh:      +9.890274e-001
   trunc:     +2.000000e+000
@@ -139,6 +142,7 @@ n: -1.100000e+000
   remainder: -2.000000e-001
   sin:       -8.912074e-001
   sinh:      -1.335647e+000
+  sqrt:      NaN
   tan:       -1.964760e+000
   tanh:      -8.004990e-001
   trunc:     -1.000000e+000
@@ -175,6 +179,7 @@ n: -3.100000e+000
   remainder: -2.000000e-001
   sin:       -4.158066e-002
   sinh:      -1.107645e+001
+  sqrt:      NaN
   tan:       +4.161665e-002
   tanh:      -9.959494e-001
   trunc:     -3.000000e+000
@@ -211,6 +216,7 @@ n: -3.800000e+000
   remainder: -2.000000e-001
   sin:       +6.118579e-001
   sinh:      -2.233941e+001
+  sqrt:      NaN
   tan:       -7.735561e-001
   tanh:      -9.989996e-001
   trunc:     -3.000000e+000