diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index cfa9787d8d..f1fce53281 100644
--- a/fpu/softfloat.c
+++ b/fpu/softfloat.c
@@ -1616,7 +1616,7 @@ int32_t float32_to_int32_round_to_zero(float32 a, float_status *status)
 | returned.
 *----------------------------------------------------------------------------*/
 
-int_fast16_t float32_to_int16_round_to_zero(float32 a, float_status *status)
+int16_t float32_to_int16_round_to_zero(float32 a, float_status *status)
 {
     flag aSign;
     int_fast16_t aExp, shiftCount;
@@ -3149,7 +3149,7 @@ int32_t float64_to_int32_round_to_zero(float64 a, float_status *status)
 | returned.
 *----------------------------------------------------------------------------*/
 
-int_fast16_t float64_to_int16_round_to_zero(float64 a, float_status *status)
+int16_t float64_to_int16_round_to_zero(float64 a, float_status *status)
 {
     flag aSign;
     int_fast16_t aExp, shiftCount;
@@ -7117,10 +7117,10 @@ uint32_t float32_to_uint32_round_to_zero(float32 a, float_status *status)
     return res;
 }
 
-int_fast16_t float32_to_int16(float32 a, float_status *status)
+int16_t float32_to_int16(float32 a, float_status *status)
 {
     int32_t v;
-    int_fast16_t res;
+    int16_t res;
     int old_exc_flags = get_float_exception_flags(status);
 
     v = float32_to_int32(a, status);
@@ -7137,10 +7137,10 @@ int_fast16_t float32_to_int16(float32 a, float_status *status)
     return res;
 }
 
-uint_fast16_t float32_to_uint16(float32 a, float_status *status)
+uint16_t float32_to_uint16(float32 a, float_status *status)
 {
     int32_t v;
-    uint_fast16_t res;
+    uint16_t res;
     int old_exc_flags = get_float_exception_flags(status);
 
     v = float32_to_int32(a, status);
@@ -7157,10 +7157,10 @@ uint_fast16_t float32_to_uint16(float32 a, float_status *status)
     return res;
 }
 
-uint_fast16_t float32_to_uint16_round_to_zero(float32 a, float_status *status)
+uint16_t float32_to_uint16_round_to_zero(float32 a, float_status *status)
 {
     int64_t v;
-    uint_fast16_t res;
+    uint16_t res;
     int old_exc_flags = get_float_exception_flags(status);
 
     v = float32_to_int64_round_to_zero(a, status);
@@ -7210,10 +7210,10 @@ uint32_t float64_to_uint32_round_to_zero(float64 a, float_status *status)
     return res;
 }
 
-int_fast16_t float64_to_int16(float64 a, float_status *status)
+int16_t float64_to_int16(float64 a, float_status *status)
 {
     int64_t v;
-    int_fast16_t res;
+    int16_t res;
     int old_exc_flags = get_float_exception_flags(status);
 
     v = float64_to_int32(a, status);
@@ -7230,10 +7230,10 @@ int_fast16_t float64_to_int16(float64 a, float_status *status)
     return res;
 }
 
-uint_fast16_t float64_to_uint16(float64 a, float_status *status)
+uint16_t float64_to_uint16(float64 a, float_status *status)
 {
     int64_t v;
-    uint_fast16_t res;
+    uint16_t res;
     int old_exc_flags = get_float_exception_flags(status);
 
     v = float64_to_int32(a, status);
@@ -7250,10 +7250,10 @@ uint_fast16_t float64_to_uint16(float64 a, float_status *status)
     return res;
 }
 
-uint_fast16_t float64_to_uint16_round_to_zero(float64 a, float_status *status)
+uint16_t float64_to_uint16_round_to_zero(float64 a, float_status *status)
 {
     int64_t v;
-    uint_fast16_t res;
+    uint16_t res;
     int old_exc_flags = get_float_exception_flags(status);
 
     v = float64_to_int64_round_to_zero(a, status);
diff --git a/include/fpu/softfloat.h b/include/fpu/softfloat.h
index 575a7398cf..624ed61661 100644
--- a/include/fpu/softfloat.h
+++ b/include/fpu/softfloat.h
@@ -362,10 +362,10 @@ extern const float16 float16_default_nan;
 /*----------------------------------------------------------------------------
 | Software IEC/IEEE single-precision conversion routines.
 *----------------------------------------------------------------------------*/
-int_fast16_t float32_to_int16(float32, float_status *status);
-uint_fast16_t float32_to_uint16(float32, float_status *status);
-int_fast16_t float32_to_int16_round_to_zero(float32, float_status *status);
-uint_fast16_t float32_to_uint16_round_to_zero(float32, float_status *status);
+int16_t float32_to_int16(float32, float_status *status);
+uint16_t float32_to_uint16(float32, float_status *status);
+int16_t float32_to_int16_round_to_zero(float32, float_status *status);
+uint16_t float32_to_uint16_round_to_zero(float32, float_status *status);
 int32_t float32_to_int32(float32, float_status *status);
 int32_t float32_to_int32_round_to_zero(float32, float_status *status);
 uint32_t float32_to_uint32(float32, float_status *status);
@@ -474,10 +474,10 @@ extern const float32 float32_default_nan;
 /*----------------------------------------------------------------------------
 | Software IEC/IEEE double-precision conversion routines.
 *----------------------------------------------------------------------------*/
-int_fast16_t float64_to_int16(float64, float_status *status);
-uint_fast16_t float64_to_uint16(float64, float_status *status);
-int_fast16_t float64_to_int16_round_to_zero(float64, float_status *status);
-uint_fast16_t float64_to_uint16_round_to_zero(float64, float_status *status);
+int16_t float64_to_int16(float64, float_status *status);
+uint16_t float64_to_uint16(float64, float_status *status);
+int16_t float64_to_int16_round_to_zero(float64, float_status *status);
+uint16_t float64_to_uint16_round_to_zero(float64, float_status *status);
 int32_t float64_to_int32(float64, float_status *status);
 int32_t float64_to_int32_round_to_zero(float64, float_status *status);
 uint32_t float64_to_uint32(float64, float_status *status);