diff --git a/src/c/arch/ffi_x86.d b/src/c/arch/ffi_x86.d
index db8b756aa..3ec2c1534 100644
--- a/src/c/arch/ffi_x86.d
+++ b/src/c/arch/ffi_x86.d
@@ -37,6 +37,10 @@ ecl_fficall_push_arg(union ecl_ffi_values *data, enum ecl_ffi_tag type)
 	case ECL_FFI_UNSIGNED_BYTE: i = data->ub; goto INT;
 	case ECL_FFI_SHORT: i = data->s; goto INT;
 	case ECL_FFI_UNSIGNED_SHORT: i = data->us; goto INT;
+#ifdef ecl_uint8_t
+        case ECL_FFI_INT8_T: i = data->i8; goto INT;
+        case ECL_FFI_UINT8_T: i = data->u8; goto INT;
+#endif
 #ifdef ecl_uint16_t
         case ECL_FFI_INT16_T: i = data->i16; goto INT;
         case ECL_FFI_UINT16_T: i = data->u16; goto INT;
@@ -123,6 +127,13 @@ ecl_fficall_execute(void *f_ptr, struct ecl_fficall *fficall, enum ecl_ffi_tag r
 	} else if (return_type == ECL_FFI_DOUBLE) {
 		fficall->output.d = ((double (*)())f_ptr)();
         }
+#ifdef ecl_uint8_t
+        else if (return_type == ECL_FFI_INT8_T) {
+                fficall->output.i8 = ((ecl_int8_t (*)())f_ptr)();
+	} else if (return_type == ECL_FFI_UINT16_T) {
+                fficall->output.u8 = ((ecl_uint8_t (*)())f_ptr)();
+	}
+#endif
 #ifdef ecl_uint16_t
         else if (return_type == ECL_FFI_INT16_T) {
                 fficall->output.i16 = ((ecl_int16_t (*)())f_ptr)();
@@ -202,11 +213,15 @@ ecl_dynamic_callback_execute(cl_object cbk_info, char *arg_buffer)
 	case ECL_FFI_UNSIGNED_CHAR: i = output.uc; goto INT;
 	case ECL_FFI_BYTE: i = output.b; goto INT;
 	case ECL_FFI_UNSIGNED_BYTE: i = output.ub; goto INT;
-#ifdef ecl_uint32_t
+#ifdef ecl_uint8_t
+	case ECL_FFI_INT8_T: i = output.i8; goto INT;
+	case ECL_FFI_UINT8_T: i = output.u8; goto INT;
+#endif
+#ifdef ecl_uint16_t
         case ECL_FFI_INT16_T:
 #endif
 	case ECL_FFI_SHORT: i = output.s; goto INT;
-#ifdef ecl_uint32_t
+#ifdef ecl_uint16_t
         case ECL_FFI_UINT16_T:
 #endif
 	case ECL_FFI_UNSIGNED_SHORT: i = output.us; goto INT;
diff --git a/src/c/arch/ffi_x86_64.d b/src/c/arch/ffi_x86_64.d
index 7e40bb1f3..8aeabd9cb 100644
--- a/src/c/arch/ffi_x86_64.d
+++ b/src/c/arch/ffi_x86_64.d
@@ -49,6 +49,10 @@ ecl_fficall_push_arg(union ecl_ffi_values *data, enum ecl_ffi_tag type)
 	switch (type) {
 	case ECL_FFI_CHAR: i = data->c;	goto INT;
 	case ECL_FFI_UNSIGNED_CHAR: i = data->uc; goto INT;
+#ifdef ecl_uint8_t
+        case ECL_FFI_INT8_T: i = data->i8; goto INT;
+        case ECL_FFI_UINT8_T: i = data->u8; goto INT;
+#endif
 	case ECL_FFI_BYTE: i = data->b; goto INT;
 	case ECL_FFI_UNSIGNED_BYTE: i = data->ub; goto INT;
 #ifdef ecl_uint16_t
@@ -160,6 +164,13 @@ ecl_fficall_execute(void *_f_ptr, struct ecl_fficall *fficall, enum ecl_ffi_tag
 	} else if (return_type == ECL_FFI_DOUBLE) {
 		fficall->output.d = ((double (*)())f_ptr)();
 	}
+#ifdef ecl_uint8_t
+        else if (return_type == ECL_FFI_INT8_T) {
+                fficall->output.i8 = ((ecl_int8_t (*)())f_ptr)();
+	} else if (return_type == ECL_FFI_UINT16_T) {
+                fficall->output.u8 = ((ecl_uint8_t (*)())f_ptr)();
+	}
+#endif
 #ifdef ecl_uint16_t
         else if (return_type == ECL_FFI_INT16_T) {
                 fficall->output.i16 = ((ecl_int16_t (*)())f_ptr)();
@@ -270,6 +281,10 @@ ARG_FROM_STACK:
 	case ECL_FFI_UNSIGNED_CHAR: i = output.uc; goto INT;
 	case ECL_FFI_BYTE: i = output.b; goto INT;
 	case ECL_FFI_UNSIGNED_BYTE: i = output.ub; goto INT;
+#ifdef ecl_uint8_t
+        case ECL_FFI_INT8_T: i = output.i8; goto INT;
+        case ECL_FFI_UINT8_T: i = output.u8; goto INT;
+#endif
 #ifdef ecl_uint16_t
         case ECL_FFI_INT16_T: i = output.i16; goto INT;
         case ECL_FFI_UINT16_T: i = output.u16; goto INT;
diff --git a/src/c/ffi.d b/src/c/ffi.d
index 0e47fdc84..014b2ecde 100644
--- a/src/c/ffi.d
+++ b/src/c/ffi.d
@@ -404,6 +404,12 @@ ecl_foreign_data_ref_elt(void *p, enum ecl_ffi_tag tag)
 		return ecl_make_unsigned_integer(*(unsigned int *)p);
 	case ECL_FFI_LONG:
 		return ecl_make_integer(*(long *)p);
+#ifdef ecl_uint8_t
+        case ECL_FFI_INT8_T:
+                return MAKE_FIXNUM(*(ecl_int8_t *)p);
+        case ECL_FFI_UINT8_T:
+                return MAKE_FIXNUM(*(ecl_uint8_t *)p);
+#endif
 #ifdef ecl_uint16_t
         case ECL_FFI_INT16_T:
                 return ecl_make_int16_t(*(ecl_int16_t *)p);
@@ -479,6 +485,12 @@ ecl_foreign_data_set_elt(void *p, enum ecl_ffi_tag tag, cl_object value)
 	case ECL_FFI_UNSIGNED_LONG:
 		*(unsigned long *)p = fixnnint(value);
 		break;
+#ifdef ecl_uint8_t
+        case ECL_FFI_INT8_T:
+                *(ecl_int8_t *)p = fixint(value);
+        case ECL_FFI_UINT8_T:
+                *(ecl_uint8_t *)p = fixnnint(value);
+#endif
 #ifdef ecl_uint16_t
         case ECL_FFI_INT16_T:
                 *(ecl_int16_t *)p = ecl_to_int16_t(value);
diff --git a/src/h/object.h b/src/h/object.h
index 002184db4..07b1b148b 100644
--- a/src/h/object.h
+++ b/src/h/object.h
@@ -786,6 +786,10 @@ union ecl_ffi_values {
 	unsigned short us;
 	long l;
 	unsigned long ul;
+#ifdef ecl_uint8_t
+        ecl_int8_t i8;
+        ecl_uint8_t u8;
+#endif
 #ifdef ecl_uint16_t
         ecl_int16_t i16;
         ecl_uint16_t u16;