diff --git a/.gitignore b/.gitignore
index 6068cbca76..2917cfbef9 100644
--- a/.gitignore
+++ b/.gitignore
@@ -35,6 +35,7 @@ massif-*
 
 # Unix-like build artifacts:
 *.o
+*.s
 
 # MSVC build artifacts:
 *.exe
diff --git a/library/Makefile b/library/Makefile
index 53c8600077..29fd3765a9 100644
--- a/library/Makefile
+++ b/library/Makefile
@@ -346,6 +346,10 @@ libmbedcrypto.dll: $(OBJS_CRYPTO)
 	echo "  CC    $<"
 	$(CC) $(LOCAL_CFLAGS) $(CFLAGS) -o $@ -c $<
 
+.c.s:
+	echo "  CC    $<"
+	$(CC) $(LOCAL_CFLAGS) $(CFLAGS) -S -o $@ -c $<
+
 .PHONY: generated_files
 generated_files: $(GENERATED_FILES)
 
@@ -396,10 +400,11 @@ $(TF_PSA_CRYPTO_CORE_PATH)/psa_crypto.o:$(TF_PSA_CRYPTO_CORE_PATH)/psa_crypto_dr
 
 clean:
 ifndef WINDOWS
-	rm -f *.o libmbed*
-	rm -f $(OBJS_CRYPTO)
+	rm -f *.o *.s libmbed*
+	rm -f $(OBJS_CRYPTO) $(OBJS_CRYPTO:.o=.s)
 else
 	if exist *.o del /Q /F *.o
+	if exist *.s del /Q /F *.s
 	if exist libmbed* del /Q /F libmbed*
 	del /Q /F del_errors_out_if_the_file_list_is_empty_but_not_if_a_file_does_not_exist $(subst /,\,$(OBJS_CRYPTO))
 endif
diff --git a/tests/scripts/components-compiler.sh b/tests/scripts/components-compiler.sh
index d89bbedae4..5d22735caf 100644
--- a/tests/scripts/components-compiler.sh
+++ b/tests/scripts/components-compiler.sh
@@ -56,7 +56,7 @@ support_test_clang_latest_opt () {
 
 component_test_clang_earliest_opt () {
     scripts/config.py full
-    test_build_opt 'full config' "$CLANG_EARLIEST" -O0
+    test_build_opt 'full config' "$CLANG_EARLIEST" -O2
 }
 
 support_test_clang_earliest_opt () {
@@ -74,7 +74,7 @@ support_test_gcc_latest_opt () {
 
 component_test_gcc_earliest_opt () {
     scripts/config.py full
-    test_build_opt 'full config' "$GCC_EARLIEST" -O0
+    test_build_opt 'full config' "$GCC_EARLIEST" -O2
 }
 
 support_test_gcc_earliest_opt () {
@@ -83,20 +83,20 @@ support_test_gcc_earliest_opt () {
 
 component_build_mingw () {
     msg "build: Windows cross build - mingw64, make (Link Library)" # ~ 30s
-    make CC=i686-w64-mingw32-gcc AR=i686-w64-mingw32-ar LD=i686-w64-minggw32-ld CFLAGS='-Werror -Wall -Wextra -maes -msse2 -mpclmul' WINDOWS_BUILD=1 lib programs
+    make CC=i686-w64-mingw32-gcc AR=i686-w64-mingw32-ar CFLAGS='-Werror -Wall -Wextra -maes -msse2 -mpclmul' WINDOWS_BUILD=1 lib programs
 
     # note Make tests only builds the tests, but doesn't run them
-    make CC=i686-w64-mingw32-gcc AR=i686-w64-mingw32-ar LD=i686-w64-minggw32-ld CFLAGS='-Werror -maes -msse2 -mpclmul' WINDOWS_BUILD=1 tests
+    make CC=i686-w64-mingw32-gcc AR=i686-w64-mingw32-ar CFLAGS='-Werror -maes -msse2 -mpclmul' WINDOWS_BUILD=1 tests
     make WINDOWS_BUILD=1 clean
 
     msg "build: Windows cross build - mingw64, make (DLL)" # ~ 30s
-    make CC=i686-w64-mingw32-gcc AR=i686-w64-mingw32-ar LD=i686-w64-minggw32-ld CFLAGS='-Werror -Wall -Wextra -maes -msse2 -mpclmul' WINDOWS_BUILD=1 SHARED=1 lib programs
-    make CC=i686-w64-mingw32-gcc AR=i686-w64-mingw32-ar LD=i686-w64-minggw32-ld CFLAGS='-Werror -Wall -Wextra -maes -msse2 -mpclmul' WINDOWS_BUILD=1 SHARED=1 tests
+    make CC=i686-w64-mingw32-gcc AR=i686-w64-mingw32-ar CFLAGS='-Werror -Wall -Wextra -maes -msse2 -mpclmul' WINDOWS_BUILD=1 SHARED=1 lib programs
+    make CC=i686-w64-mingw32-gcc AR=i686-w64-mingw32-ar CFLAGS='-Werror -Wall -Wextra -maes -msse2 -mpclmul' WINDOWS_BUILD=1 SHARED=1 tests
     make WINDOWS_BUILD=1 clean
 
     msg "build: Windows cross build - mingw64, make (Library only, default config without MBEDTLS_AESNI_C)" # ~ 30s
     ./scripts/config.py unset MBEDTLS_AESNI_C #
-    make CC=i686-w64-mingw32-gcc AR=i686-w64-mingw32-ar LD=i686-w64-minggw32-ld CFLAGS='-Werror -Wall -Wextra' WINDOWS_BUILD=1 lib
+    make CC=i686-w64-mingw32-gcc AR=i686-w64-mingw32-ar CFLAGS='-Werror -Wall -Wextra' WINDOWS_BUILD=1 lib
     make WINDOWS_BUILD=1 clean
 }
 
diff --git a/tests/scripts/components-configuration-crypto.sh b/tests/scripts/components-configuration-crypto.sh
index 5ce69b527a..edb73a09a6 100644
--- a/tests/scripts/components-configuration-crypto.sh
+++ b/tests/scripts/components-configuration-crypto.sh
@@ -1968,7 +1968,7 @@ component_test_psa_crypto_config_accel_des () {
     helper_libtestdriver1_make_main "$loc_accel_list"
 
     # Make sure this was not re-enabled by accident (additive config)
-    not grep mbedtls_des* ${BUILTIN_SRC_PATH}/des.o
+    not grep mbedtls_des ${BUILTIN_SRC_PATH}/des.o
 
     # Run the tests
     # -------------
diff --git a/tests/scripts/components-platform.sh b/tests/scripts/components-platform.sh
index fd858a7696..a8a0f7678c 100644
--- a/tests/scripts/components-platform.sh
+++ b/tests/scripts/components-platform.sh
@@ -222,49 +222,53 @@ component_build_aes_armce () {
     scripts/config.py set MBEDTLS_AES_USE_HARDWARE_ONLY
 
     msg "MBEDTLS_AES_USE_HARDWARE_ONLY, clang, aarch64"
-    make -B library/../${BUILTIN_SRC_PATH}/aesce.o CC=clang CFLAGS="--target=aarch64-linux-gnu -march=armv8-a+crypto"
+    make -B library/../${BUILTIN_SRC_PATH}/aesce.o library/../${BUILTIN_SRC_PATH}/aesce.s CC=clang CFLAGS="--target=aarch64-linux-gnu -march=armv8-a+crypto"
+    msg "clang, test aarch64 crypto instructions built"
+    grep -E 'aes[a-z]+\s*[qv]' ${BUILTIN_SRC_PATH}/aesce.s
 
     msg "MBEDTLS_AES_USE_HARDWARE_ONLY, clang, arm"
-    make -B library/../${BUILTIN_SRC_PATH}/aesce.o CC=clang CFLAGS="--target=arm-linux-gnueabihf -mcpu=cortex-a72+crypto -marm"
+    make -B library/../${BUILTIN_SRC_PATH}/aesce.o library/../${BUILTIN_SRC_PATH}/aesce.s CC=clang CFLAGS="--target=arm-linux-gnueabihf -mcpu=cortex-a72+crypto -marm"
+    msg "clang, test A32 crypto instructions built"
+    grep -E 'aes[0-9a-z]+.[0-9]\s*[qv]' ${BUILTIN_SRC_PATH}/aesce.s
 
     msg "MBEDTLS_AES_USE_HARDWARE_ONLY, clang, thumb"
-    make -B library/../${BUILTIN_SRC_PATH}/aesce.o CC=clang CFLAGS="--target=arm-linux-gnueabihf -mcpu=cortex-a32+crypto -mthumb"
-
-    scripts/config.py unset MBEDTLS_AES_USE_HARDWARE_ONLY
-
-    msg "no MBEDTLS_AES_USE_HARDWARE_ONLY, clang, aarch64"
-    make -B library/../${BUILTIN_SRC_PATH}/aesce.o CC=clang CFLAGS="--target=aarch64-linux-gnu -march=armv8-a+crypto"
-
-    msg "no MBEDTLS_AES_USE_HARDWARE_ONLY, clang, arm"
-    make -B library/../${BUILTIN_SRC_PATH}/aesce.o CC=clang CFLAGS="--target=arm-linux-gnueabihf -mcpu=cortex-a72+crypto -marm"
-
-    msg "no MBEDTLS_AES_USE_HARDWARE_ONLY, clang, thumb"
-    make -B library/../${BUILTIN_SRC_PATH}/aesce.o CC=clang CFLAGS="--target=arm-linux-gnueabihf -mcpu=cortex-a32+crypto -mthumb"
-
-    # test for presence of AES instructions
-    scripts/config.py set MBEDTLS_AES_USE_HARDWARE_ONLY
-    msg "clang, test A32 crypto instructions built"
-    make -B library/../${BUILTIN_SRC_PATH}/aesce.o CC=clang CFLAGS="--target=arm-linux-gnueabihf -mcpu=cortex-a72+crypto -marm -S"
-    grep -E 'aes[0-9a-z]+.[0-9]\s*[qv]' ${BUILTIN_SRC_PATH}/aesce.o
+    make -B library/../${BUILTIN_SRC_PATH}/aesce.o library/../${BUILTIN_SRC_PATH}/aesce.s CC=clang CFLAGS="--target=arm-linux-gnueabihf -mcpu=cortex-a32+crypto -mthumb"
     msg "clang, test T32 crypto instructions built"
-    make -B library/../${BUILTIN_SRC_PATH}/aesce.o CC=clang CFLAGS="--target=arm-linux-gnueabihf -mcpu=cortex-a32+crypto -mthumb -S"
-    grep -E 'aes[0-9a-z]+.[0-9]\s*[qv]' ${BUILTIN_SRC_PATH}/aesce.o
-    msg "clang, test aarch64 crypto instructions built"
-    make -B library/../${BUILTIN_SRC_PATH}/aesce.o CC=clang CFLAGS="--target=aarch64-linux-gnu -march=armv8-a -S"
-    grep -E 'aes[a-z]+\s*[qv]' ${BUILTIN_SRC_PATH}/aesce.o
+    grep -E 'aes[0-9a-z]+.[0-9]\s*[qv]' ${BUILTIN_SRC_PATH}/aesce.s
 
-    # test for absence of AES instructions
     scripts/config.py unset MBEDTLS_AES_USE_HARDWARE_ONLY
+
+    msg "MBEDTLS_AES_USE_both, clang, aarch64"
+    make -B library/../${BUILTIN_SRC_PATH}/aesce.o library/../${BUILTIN_SRC_PATH}/aesce.s CC=clang CFLAGS="--target=aarch64-linux-gnu -march=armv8-a+crypto"
+    msg "clang, test aarch64 crypto instructions built"
+    grep -E 'aes[a-z]+\s*[qv]' ${BUILTIN_SRC_PATH}/aesce.s
+
+    msg "MBEDTLS_AES_USE_both, clang, arm"
+    make -B library/../${BUILTIN_SRC_PATH}/aesce.o library/../${BUILTIN_SRC_PATH}/aesce.s CC=clang CFLAGS="--target=arm-linux-gnueabihf -mcpu=cortex-a72+crypto -marm"
+    msg "clang, test A32 crypto instructions built"
+    grep -E 'aes[0-9a-z]+.[0-9]\s*[qv]' ${BUILTIN_SRC_PATH}/aesce.s
+
+    msg "MBEDTLS_AES_USE_both, clang, thumb"
+    make -B library/../${BUILTIN_SRC_PATH}/aesce.o library/../${BUILTIN_SRC_PATH}/aesce.s CC=clang CFLAGS="--target=arm-linux-gnueabihf -mcpu=cortex-a32+crypto -mthumb"
+    msg "clang, test T32 crypto instructions built"
+    grep -E 'aes[0-9a-z]+.[0-9]\s*[qv]' ${BUILTIN_SRC_PATH}/aesce.s
+
     scripts/config.py unset MBEDTLS_AESCE_C
-    msg "clang, test A32 crypto instructions not built"
-    make -B library/../${BUILTIN_SRC_PATH}/aesce.o CC=clang CFLAGS="--target=arm-linux-gnueabihf -mcpu=cortex-a72+crypto -marm -S"
-    not grep -E 'aes[0-9a-z]+.[0-9]\s*[qv]' ${BUILTIN_SRC_PATH}/aesce.o
-    msg "clang, test T32 crypto instructions not built"
-    make -B library/../${BUILTIN_SRC_PATH}/aesce.o CC=clang CFLAGS="--target=arm-linux-gnueabihf -mcpu=cortex-a32+crypto -mthumb -S"
-    not grep -E 'aes[0-9a-z]+.[0-9]\s*[qv]' ${BUILTIN_SRC_PATH}/aesce.o
+
+    msg "no MBEDTLS_AESCE_C, clang, aarch64"
+    make -B library/../${BUILTIN_SRC_PATH}/aesce.o library/../${BUILTIN_SRC_PATH}/aesce.s CC=clang CFLAGS="--target=aarch64-linux-gnu -march=armv8-a"
     msg "clang, test aarch64 crypto instructions not built"
-    make -B library/../${BUILTIN_SRC_PATH}/aesce.o CC=clang CFLAGS="--target=aarch64-linux-gnu -march=armv8-a -S"
-    not grep -E 'aes[a-z]+\s*[qv]' ${BUILTIN_SRC_PATH}/aesce.o
+    not grep -E 'aes[a-z]+\s*[qv]' ${BUILTIN_SRC_PATH}/aesce.s
+
+    msg "no MBEDTLS_AESCE_C, clang, arm"
+    make -B library/../${BUILTIN_SRC_PATH}/aesce.o library/../${BUILTIN_SRC_PATH}/aesce.s CC=clang CFLAGS="--target=arm-linux-gnueabihf -mcpu=cortex-a72 -marm"
+    msg "clang, test A32 crypto instructions not built"
+    not grep -E 'aes[0-9a-z]+.[0-9]\s*[qv]' ${BUILTIN_SRC_PATH}/aesce.s
+
+    msg "no MBEDTLS_AESCE_C, clang, thumb"
+    make -B library/../${BUILTIN_SRC_PATH}/aesce.o library/../${BUILTIN_SRC_PATH}/aesce.s CC=clang CFLAGS="--target=arm-linux-gnueabihf -mcpu=cortex-a32 -mthumb"
+    msg "clang, test T32 crypto instructions not built"
+    not grep -E 'aes[0-9a-z]+.[0-9]\s*[qv]' ${BUILTIN_SRC_PATH}/aesce.s
 }
 
 support_build_sha_armce () {
@@ -275,67 +279,59 @@ support_build_sha_armce () {
 component_build_sha_armce () {
     scripts/config.py unset MBEDTLS_SHA256_USE_ARMV8_A_CRYPTO_IF_PRESENT
 
-
     # Test variations of SHA256 Armv8 crypto extensions
     scripts/config.py set MBEDTLS_SHA256_USE_ARMV8_A_CRYPTO_ONLY
         msg "MBEDTLS_SHA256_USE_ARMV8_A_CRYPTO_ONLY clang, aarch64"
-        make -B library/../${BUILTIN_SRC_PATH}/sha256.o CC=clang CFLAGS="--target=aarch64-linux-gnu -march=armv8-a"
+        make -B library/../${BUILTIN_SRC_PATH}/sha256.o library/../${BUILTIN_SRC_PATH}/sha256.s CC=clang CFLAGS="--target=aarch64-linux-gnu -march=armv8-a+crypto"
+        msg "MBEDTLS_SHA256_USE_ARMV8_A_CRYPTO_ONLY clang, test aarch64 crypto instructions built"
+        grep -E 'sha256[a-z0-9]+\s+[qv]' ${BUILTIN_SRC_PATH}/sha256.s
+
         msg "MBEDTLS_SHA256_USE_ARMV8_A_CRYPTO_ONLY clang, arm"
-        make -B library/../${BUILTIN_SRC_PATH}/sha256.o CC=clang CFLAGS="--target=arm-linux-gnueabihf -mcpu=cortex-a72+crypto -marm"
+        make -B library/../${BUILTIN_SRC_PATH}/sha256.o library/../${BUILTIN_SRC_PATH}/sha256.s CC=clang CFLAGS="--target=arm-linux-gnueabihf -mcpu=cortex-a72+crypto -marm"
+        msg "MBEDTLS_SHA256_USE_ARMV8_A_CRYPTO_ONLY clang, test A32 crypto instructions built"
+        grep -E 'sha256[a-z0-9]+.32\s+[qv]' ${BUILTIN_SRC_PATH}/sha256.s
     scripts/config.py unset MBEDTLS_SHA256_USE_ARMV8_A_CRYPTO_ONLY
 
 
     # test the deprecated form of the config option
     scripts/config.py set MBEDTLS_SHA256_USE_A64_CRYPTO_ONLY
         msg "MBEDTLS_SHA256_USE_A64_CRYPTO_ONLY clang, thumb"
-        make -B library/../${BUILTIN_SRC_PATH}/sha256.o CC=clang CFLAGS="--target=arm-linux-gnueabihf -mcpu=cortex-a32+crypto -mthumb"
+        make -B library/../${BUILTIN_SRC_PATH}/sha256.o library/../${BUILTIN_SRC_PATH}/sha256.s CC=clang CFLAGS="--target=arm-linux-gnueabihf -mcpu=cortex-a32+crypto -mthumb"
+        msg "MBEDTLS_SHA256_USE_A64_CRYPTO_ONLY clang, test T32 crypto instructions built"
+        grep -E 'sha256[a-z0-9]+.32\s+[qv]' ${BUILTIN_SRC_PATH}/sha256.s
     scripts/config.py unset MBEDTLS_SHA256_USE_A64_CRYPTO_ONLY
 
     scripts/config.py set MBEDTLS_SHA256_USE_ARMV8_A_CRYPTO_IF_PRESENT
         msg "MBEDTLS_SHA256_USE_ARMV8_A_CRYPTO_IF_PRESENT clang, aarch64"
-        make -B library/../${BUILTIN_SRC_PATH}/sha256.o CC=clang CFLAGS="--target=aarch64-linux-gnu -march=armv8-a"
+        make -B library/../${BUILTIN_SRC_PATH}/sha256.o library/../${BUILTIN_SRC_PATH}/sha256.s CC=clang CFLAGS="--target=aarch64-linux-gnu -march=armv8-a+crypto"
+        msg "MBEDTLS_SHA256_USE_ARMV8_A_CRYPTO_IF_PRESENT clang, test aarch64 crypto instructions built"
+        grep -E 'sha256[a-z0-9]+\s+[qv]' ${BUILTIN_SRC_PATH}/sha256.s
     scripts/config.py unset MBEDTLS_SHA256_USE_ARMV8_A_CRYPTO_IF_PRESENT
 
 
     # test the deprecated form of the config option
     scripts/config.py set MBEDTLS_SHA256_USE_A64_CRYPTO_IF_PRESENT
         msg "MBEDTLS_SHA256_USE_A64_CRYPTO_IF_PRESENT clang, arm"
-        make -B library/../${BUILTIN_SRC_PATH}/sha256.o CC=clang CFLAGS="--target=arm-linux-gnueabihf -mcpu=cortex-a72+crypto -marm -std=c99"
+        make -B library/../${BUILTIN_SRC_PATH}/sha256.o library/../${BUILTIN_SRC_PATH}/sha256.s CC=clang CFLAGS="--target=arm-linux-gnueabihf -mcpu=cortex-a72+crypto -marm -std=c99"
+
         msg "MBEDTLS_SHA256_USE_A64_CRYPTO_IF_PRESENT clang, thumb"
-        make -B library/../${BUILTIN_SRC_PATH}/sha256.o CC=clang CFLAGS="--target=arm-linux-gnueabihf -mcpu=cortex-a32+crypto -mthumb"
+        make -B library/../${BUILTIN_SRC_PATH}/sha256.o library/../${BUILTIN_SRC_PATH}/sha256.s CC=clang CFLAGS="--target=arm-linux-gnueabihf -mcpu=cortex-a32+crypto -mthumb"
+        msg "MBEDTLS_SHA256_USE_A64_CRYPTO_IF_PRESENT clang, test T32 crypto instructions built"
+        grep -E 'sha256[a-z0-9]+.32\s+[qv]' ${BUILTIN_SRC_PATH}/sha256.s
     scripts/config.py unset MBEDTLS_SHA256_USE_A64_CRYPTO_IF_PRESENT
 
-
-    # examine the disassembly for presence of SHA instructions
-    for opt in MBEDTLS_SHA256_USE_ARMV8_A_CRYPTO_ONLY MBEDTLS_SHA256_USE_ARMV8_A_CRYPTO_IF_PRESENT; do
-        scripts/config.py set ${opt}
-            msg "${opt} clang, test A32 crypto instructions built"
-            make -B library/../${BUILTIN_SRC_PATH}/sha256.o CC=clang CFLAGS="--target=arm-linux-gnueabihf -mcpu=cortex-a72+crypto -marm -S"
-            grep -E 'sha256[a-z0-9]+.32\s+[qv]' ${BUILTIN_SRC_PATH}/sha256.o
-
-            msg "${opt} clang, test T32 crypto instructions built"
-            make -B library/../${BUILTIN_SRC_PATH}/sha256.o CC=clang CFLAGS="--target=arm-linux-gnueabihf -mcpu=cortex-a32+crypto -mthumb -S"
-            grep -E 'sha256[a-z0-9]+.32\s+[qv]' ${BUILTIN_SRC_PATH}/sha256.o
-
-            msg "${opt} clang, test aarch64 crypto instructions built"
-            make -B library/../${BUILTIN_SRC_PATH}/sha256.o CC=clang CFLAGS="--target=aarch64-linux-gnu -march=armv8-a -S"
-            grep -E 'sha256[a-z0-9]+\s+[qv]' ${BUILTIN_SRC_PATH}/sha256.o
-        scripts/config.py unset ${opt}
-    done
-
-
     # examine the disassembly for absence of SHA instructions
     msg "clang, test A32 crypto instructions not built"
-    make -B library/../${BUILTIN_SRC_PATH}/sha256.o CC=clang CFLAGS="--target=arm-linux-gnueabihf -mcpu=cortex-a72+crypto -marm -S"
-    not grep -E 'sha256[a-z0-9]+.32\s+[qv]' ${BUILTIN_SRC_PATH}/sha256.o
+    make -B library/../${BUILTIN_SRC_PATH}/sha256.s CC=clang CFLAGS="--target=arm-linux-gnueabihf -mcpu=cortex-a72 -marm"
+    not grep -E 'sha256[a-z0-9]+.32\s+[qv]' ${BUILTIN_SRC_PATH}/sha256.s
 
     msg "clang, test T32 crypto instructions not built"
-    make -B library/../${BUILTIN_SRC_PATH}/sha256.o CC=clang CFLAGS="--target=arm-linux-gnueabihf -mcpu=cortex-a32+crypto -mthumb -S"
-    not grep -E 'sha256[a-z0-9]+.32\s+[qv]' ${BUILTIN_SRC_PATH}/sha256.o
+    make -B library/../${BUILTIN_SRC_PATH}/sha256.s CC=clang CFLAGS="--target=arm-linux-gnueabihf -mcpu=cortex-a32 -mthumb"
+    not grep -E 'sha256[a-z0-9]+.32\s+[qv]' ${BUILTIN_SRC_PATH}/sha256.s
 
     msg "clang, test aarch64 crypto instructions not built"
-    make -B library/../${BUILTIN_SRC_PATH}/sha256.o CC=clang CFLAGS="--target=aarch64-linux-gnu -march=armv8-a -S"
-    not grep -E 'sha256[a-z0-9]+\s+[qv]' ${BUILTIN_SRC_PATH}/sha256.o
+    make -B library/../${BUILTIN_SRC_PATH}/sha256.s CC=clang CFLAGS="--target=aarch64-linux-gnu -march=armv8-a"
+    not grep -E 'sha256[a-z0-9]+\s+[qv]' ${BUILTIN_SRC_PATH}/sha256.s
 }
 
 component_build_arm_none_eabi_gcc () {