diff --git a/.gitignore b/.gitignore
index 19506df..8737c25 100644
--- a/.gitignore
+++ b/.gitignore
@@ -15,6 +15,12 @@
 /.libs
 test_*.txt
 
+*.gcda
+*.gcno
+*.info
+coverage/
+compat_reports/
+
 test
 test.exe
 mtest
diff --git a/demo/test.c b/demo/test.c
index 5ee2d1e..f9bff08 100644
--- a/demo/test.c
+++ b/demo/test.c
@@ -427,6 +427,9 @@ draw(&a);draw(&b);draw(&c);draw(&d);
                  printf("d == %lu\n", ix);
                  return 0;
               }
+       } else if (!strcmp(cmd, "exit")) {
+              printf("\nokay, exiting now\n");
+              return 0;
        }
 
    }
diff --git a/makefile b/makefile
index 832b1ec..894ff6e 100644
--- a/makefile
+++ b/makefile
@@ -141,6 +141,9 @@ test_standalone: CFLAGS+=-DTFM_DEMO_TEST_VS_MTEST=0
 test_standalone: $(LIBNAME) demo/test.o
 	$(CC) $(CFLAGS) demo/test.o $(LIBNAME) $(PROF) -o test
 
+testme: test mtest
+	./mtest/mtest -15 | ./test
+
 timing: $(LIBNAME) demo/timing.o
 	$(CC) $(CFLAGS) demo/timing.o $(LIBNAME) $(PROF) -o timing
 
@@ -151,7 +154,33 @@ profiled:
 	rm -f `find . -type f -name "*.a" | xargs`
 	rm -f test
 	CC=$(CC) PREFIX="${PREFIX} CFLAGS="${CFLAGS} -fprofile-use" MAKE=${MAKE} ${MAKE} timing
-	
+
+# target that pre-processes all coverage data
+lcov-single-create:
+	lcov --capture --no-external --directory src -q --output-file coverage_std.info
+
+# target that removes all coverage output
+cleancov-clean:
+	rm -f `find . -type f -name "*.info" | xargs`
+	rm -rf coverage/
+
+# generates html output from all coverage_*.info files
+lcov:
+	lcov `find -name 'coverage_*.info' -exec echo -n " -a {}" \;` -o coverage.info -q 2>/dev/null
+	genhtml coverage.info --output-directory coverage
+
+# combines all necessary steps to create the coverage from a single testrun with e.g.
+lcov-single: | cleancov-clean lcov-single-create lcov
+
+
+#make the code coverage of the library
+coverage: CFLAGS += -fprofile-arcs -ftest-coverage
+coverage: LDFLAGS += -lgcov
+coverage: LIB_PRE = -Wl,--whole-archive
+coverage: LIB_POST = -Wl,--no-whole-archive
+
+coverage: | testme lcov-single
+
 stest: $(LIBNAME) demo/stest.o
 	$(CC) $(CFLAGS) demo/stest.o $(LIBNAME) -o stest
 
diff --git a/mtest/mtest.c b/mtest/mtest.c
index f8a62a8..0dbb5db 100644
--- a/mtest/mtest.c
+++ b/mtest/mtest.c
@@ -38,7 +38,6 @@ mulmod
 #include <stdlib.h>
 #include <time.h>
 #include <tommath.h>
-#define CRYPT
 #undef DIGIT_BIT
 #include "../src/headers/tfm.h"
 
@@ -72,8 +71,9 @@ void rand_num2(mp_int *a)
 
 #define mp_to64(a, b) mp_toradix_n(a, b, 64, sizeof(b))
 
-int main(void)
+int main(int argc, char *argv[])
 {
+   long long max;
    int n, tmp;
    mp_int a, b, c, d, e;
 #ifdef MTEST_NO_FULLSPEED
@@ -88,6 +88,27 @@ int main(void)
    mp_init(&e);
 
 
+   if (argc > 1) {
+       max = strtol(argv[1], NULL, 0);
+       printf("%lld\n", max);
+       if (max < 0) {
+           max = -max;
+           printf("%lld\n", max);
+           if (max < 64) {
+               unsigned long long m = (1ULL << (max)) + 1;
+               max = (long long)m;
+           } else {
+               max = 1;
+           }
+           printf("%lld\n", max);
+       } else if (max == 0) {
+           max = 1;
+       }
+   }
+   else {
+       max = 0;
+   }
+
    /* initial (2^n - 1)^2 testing, makes sure the comba multiplier works [it has the new carry code] */
 /*
    mp_set(&a, 1);
@@ -125,6 +146,11 @@ int main(void)
       }
 #endif
        n = fgetc(rng) % 16;
+       if (max != 0) {
+           --max;
+           if (max == 0)
+             n = 255;
+       }
    if (n == 0) {
        /* add tests */
        rand_num(&a);
@@ -318,6 +344,9 @@ int main(void)
       printf("%s\n%d\n", buf, tmp);
       mp_to64(&b, buf);
       printf("%s\n", buf);
+   } else if (n == 255) {
+      printf("exit\n");
+      break;
    }
    }
    fclose(rng);