diff --git a/.gitignore b/.gitignore
index 1ea0a323d92..5706c86ae3f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -59,6 +59,7 @@ lcov*.info
 /*-fake.rb
 /*.dll
 /*.exe
+/coroutine-test
 /*.ilk
 /*.res
 /*.pc
diff --git a/common.mk b/common.mk
index e6559c6ca41..c6c76717750 100644
--- a/common.mk
+++ b/common.mk
@@ -94,6 +94,13 @@ MAKE_ENC      = -f $(ENC_MK) V="$(V)" UNICODE_HDR_DIR="$(UNICODE_HDR_DIR)" \
 
 PRISM_BUILD_DIR = prism
 
+COROUTINE_TEST = coroutine-test$(EXEEXT)
+COROUTINE_TEST_OBJS = coroutine-main.$(OBJEXT) \
+		coroutine-stack.$(OBJEXT) \
+		coroutine-test_initialize_destroy.$(OBJEXT) \
+		coroutine-test_transfer_repeat.$(OBJEXT) \
+		coroutine-test_transfer_return.$(OBJEXT)
+
 LIBPRISM_OBJS = \
 		prism/arena.$(OBJEXT) \
 		prism/buffer.$(OBJEXT) \
@@ -691,6 +698,7 @@ noarch_config_h = tmp/include/noarch/ruby/config.h
 clean: clean-ext clean-enc clean-golf clean-docs clean-extout clean-modular-gc clean-local clean-platform clean-spec
 clean-local:: clean-runnable
 	$(Q)$(RM) $(ALLOBJS) $(LIBRUBY_A) $(LIBRUBY_SO) $(LIBRUBY) $(LIBRUBY_ALIASES)
+	$(Q)$(RM) $(COROUTINE_TEST) $(COROUTINE_TEST_OBJS)
 	$(Q)$(RM) $(PROGRAM) $(WPROGRAM) miniruby$(EXEEXT) dmyext.$(OBJEXT) dmyenc.$(OBJEXT) $(ARCHFILE) .*.time
 	$(Q)$(RM) y.tab.c y.output encdb.h transdb.h config.log rbconfig.rb $(ruby_pc) $(COROUTINE_H:/Context.h=/.time)
 	$(Q)$(RM) probes.h probes.$(OBJEXT) probes.stamp ruby-glommed.$(OBJEXT) ruby.imp ChangeLog $(STATIC_RUBY)$(EXEEXT)
@@ -931,8 +939,15 @@ yes-test-tool: prog PHONY
 	$(ACTIONS_ENDGROUP)
 no-test-tool: PHONY
 
+test-coroutine: $(TEST_RUNNABLE)-test-coroutine
+yes-test-coroutine: $(COROUTINE_TEST) PHONY
+	$(ACTIONS_GROUP)
+	$(Q)$(exec) $(COROUTINE_TEST_RUN)
+	$(ACTIONS_ENDGROUP)
+no-test-coroutine: PHONY
+
 test-sample: test-basic # backward compatibility for mswin-build
-test-short: btest-ruby $(DOT_WAIT) test-knownbug $(DOT_WAIT) test-basic
+test-short: test-coroutine $(DOT_WAIT) btest-ruby $(DOT_WAIT) test-knownbug $(DOT_WAIT) test-basic
 test: test-short
 
 # Separate to skip updating encs and exts by `make -o test-precheck`
@@ -1043,7 +1058,7 @@ $(ENC_MK): $(srcdir)/enc/make_encmake.rb $(srcdir)/enc/Makefile.in $(srcdir)/enc
 .PHONY: distclean-srcs distclean-srcs-local distclean-srcs-ext
 .PHONY: realclean realclean-ext realclean-local realclean-enc realclean-golf realclean-extout
 .PHONY: realclean-srcs realclean-srcs-local realclean-srcs-ext
-.PHONY: exam check test test-short test-all btest btest-ruby test-basic test-knownbug
+.PHONY: exam check test test-short test-all test-coroutine btest btest-ruby test-basic test-knownbug
 .PHONY: run runruby parse benchmark gdb gdb-ruby
 .PHONY: update-mspec update-rubyspec test-rubyspec test-spec
 .PHONY: touch-unicode-files
@@ -1137,6 +1152,30 @@ $(COROUTINE_H:/Context.h=/.time):
 	$(Q) $(MAKEDIRS) $(@D)
 	@$(NULLCMD) > $@
 
+$(COROUTINE_TEST): $(COROUTINE_TEST_OBJS) $(COROUTINE_OBJ)
+	$(ECHO) linking $@
+	$(Q) $(COROUTINE_TEST_LINK)
+
+coroutine-main.$(OBJEXT): {$(VPATH)}coroutine/test/main.c
+	$(ECHO) compiling $(srcdir)/coroutine/test/main.c
+	$(Q) $(CC) $(CFLAGS) $(XCFLAGS) $(CPPFLAGS) $(COUTFLAG)$@ -c $(CSRCFLAG)$(srcdir)/coroutine/test/main.c
+
+coroutine-stack.$(OBJEXT): {$(VPATH)}coroutine/test/stack.c
+	$(ECHO) compiling $(srcdir)/coroutine/test/stack.c
+	$(Q) $(CC) $(CFLAGS) $(XCFLAGS) $(CPPFLAGS) $(COUTFLAG)$@ -c $(CSRCFLAG)$(srcdir)/coroutine/test/stack.c
+
+coroutine-test_initialize_destroy.$(OBJEXT): {$(VPATH)}coroutine/test/test_initialize_destroy.c
+	$(ECHO) compiling $(srcdir)/coroutine/test/test_initialize_destroy.c
+	$(Q) $(CC) $(CFLAGS) $(XCFLAGS) $(CPPFLAGS) $(COUTFLAG)$@ -c $(CSRCFLAG)$(srcdir)/coroutine/test/test_initialize_destroy.c
+
+coroutine-test_transfer_repeat.$(OBJEXT): {$(VPATH)}coroutine/test/test_transfer_repeat.c
+	$(ECHO) compiling $(srcdir)/coroutine/test/test_transfer_repeat.c
+	$(Q) $(CC) $(CFLAGS) $(XCFLAGS) $(CPPFLAGS) $(COUTFLAG)$@ -c $(CSRCFLAG)$(srcdir)/coroutine/test/test_transfer_repeat.c
+
+coroutine-test_transfer_return.$(OBJEXT): {$(VPATH)}coroutine/test/test_transfer_return.c
+	$(ECHO) compiling $(srcdir)/coroutine/test/test_transfer_return.c
+	$(Q) $(CC) $(CFLAGS) $(XCFLAGS) $(CPPFLAGS) $(COUTFLAG)$@ -c $(CSRCFLAG)$(srcdir)/coroutine/test/test_transfer_return.c
+
 ###
 
 # dependencies for generated C sources.
diff --git a/coroutine/test/main.c b/coroutine/test/main.c
new file mode 100644
index 00000000000..7340ab7e736
--- /dev/null
+++ b/coroutine/test/main.c
@@ -0,0 +1,31 @@
+#include "test_initialize_destroy.h"
+#include "test_transfer_repeat.h"
+#include "test_transfer_return.h"
+
+#include <stdlib.h>
+
+static int
+run_tests(void)
+{
+    int result = EXIT_SUCCESS;
+
+    if (test_initialize_destroy() != EXIT_SUCCESS) result = EXIT_FAILURE;
+    if (test_transfer_repeat() != EXIT_SUCCESS) result = EXIT_FAILURE;
+    if (test_transfer_return() != EXIT_SUCCESS) result = EXIT_FAILURE;
+
+    return result;
+}
+
+int
+main(void)
+{
+    return run_tests();
+}
+
+#if defined(_WIN32)
+int
+wmain(void)
+{
+    return run_tests();
+}
+#endif
diff --git a/coroutine/test/stack.c b/coroutine/test/stack.c
new file mode 100644
index 00000000000..0bc98799654
--- /dev/null
+++ b/coroutine/test/stack.c
@@ -0,0 +1,49 @@
+#include "ruby/internal/config.h"
+
+#include "stack.h"
+
+#include <stdlib.h>
+
+#if defined(_WIN32)
+# include <windows.h>
+#elif defined(HAVE_SYS_MMAN_H)
+# include <sys/mman.h>
+#endif
+
+#if !defined(MAP_ANONYMOUS) && defined(MAP_ANON)
+# define MAP_ANONYMOUS MAP_ANON
+#endif
+
+int
+coroutine_stack_allocate(struct coroutine_stack *stack, size_t size)
+{
+#if defined(_WIN32)
+    stack->base = VirtualAlloc(NULL, size, MEM_COMMIT | MEM_RESERVE, PAGE_READWRITE);
+#elif defined(HAVE_MMAP) && defined(MAP_ANONYMOUS)
+    stack->base = mmap(NULL, size, PROT_READ | PROT_WRITE,
+                       MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+    if (stack->base == MAP_FAILED) stack->base = NULL;
+#else
+    stack->base = malloc(size);
+#endif
+
+    stack->size = stack->base == NULL ? 0 : size;
+    return stack->base == NULL ? -1 : 0;
+}
+
+void
+coroutine_stack_free(struct coroutine_stack *stack)
+{
+    if (stack->base == NULL) return;
+
+#if defined(_WIN32)
+    VirtualFree(stack->base, 0, MEM_RELEASE);
+#elif defined(HAVE_MMAP) && defined(MAP_ANONYMOUS)
+    munmap(stack->base, stack->size);
+#else
+    free(stack->base);
+#endif
+
+    stack->base = NULL;
+    stack->size = 0;
+}
diff --git a/coroutine/test/stack.h b/coroutine/test/stack.h
new file mode 100644
index 00000000000..1ec63730e75
--- /dev/null
+++ b/coroutine/test/stack.h
@@ -0,0 +1,11 @@
+#pragma once
+
+#include <stddef.h>
+
+struct coroutine_stack {
+    void *base;
+    size_t size;
+};
+
+int coroutine_stack_allocate(struct coroutine_stack *stack, size_t size);
+void coroutine_stack_free(struct coroutine_stack *stack);
diff --git a/coroutine/test/test_initialize_destroy.c b/coroutine/test/test_initialize_destroy.c
new file mode 100644
index 00000000000..2762ae70c06
--- /dev/null
+++ b/coroutine/test/test_initialize_destroy.c
@@ -0,0 +1,41 @@
+#include "ruby/internal/config.h"
+
+#include COROUTINE_H
+
+#include "stack.h"
+#include "test_initialize_destroy.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#define STACK_SIZE (1024 * 1024)
+
+static COROUTINE
+never_started(struct coroutine_context *from, struct coroutine_context *self)
+{
+    (void)from;
+    (void)self;
+    abort();
+}
+
+int
+test_initialize_destroy(void)
+{
+    struct coroutine_stack stack = {0};
+    struct coroutine_context main_context;
+    struct coroutine_context context;
+
+    if (coroutine_stack_allocate(&stack, STACK_SIZE) != 0) {
+        fprintf(stderr, "failed to allocate coroutine stack\n");
+        return EXIT_FAILURE;
+    }
+
+    coroutine_initialize_main(&main_context);
+    coroutine_initialize(&context, never_started, stack.base, stack.size);
+
+    coroutine_destroy(&context);
+    coroutine_destroy(&main_context);
+    coroutine_stack_free(&stack);
+
+    return EXIT_SUCCESS;
+}
diff --git a/coroutine/test/test_initialize_destroy.h b/coroutine/test/test_initialize_destroy.h
new file mode 100644
index 00000000000..5bb4a2a5671
--- /dev/null
+++ b/coroutine/test/test_initialize_destroy.h
@@ -0,0 +1,3 @@
+#pragma once
+
+int test_initialize_destroy(void);
diff --git a/coroutine/test/test_transfer_repeat.c b/coroutine/test/test_transfer_repeat.c
new file mode 100644
index 00000000000..50a6f971116
--- /dev/null
+++ b/coroutine/test/test_transfer_repeat.c
@@ -0,0 +1,141 @@
+#include "ruby/internal/config.h"
+
+#include COROUTINE_H
+
+#include "stack.h"
+#include "test_transfer_repeat.h"
+
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#define STACK_SIZE (1024 * 1024)
+#define TRANSFER_COUNT 1000
+
+static struct coroutine_context main_context;
+static struct coroutine_context worker_context;
+static unsigned int yielded_iteration;
+static uint32_t yielded_state;
+static int completed;
+
+static void
+check_context(const char *message, struct coroutine_context *actual,
+              struct coroutine_context *expected)
+{
+    if (actual != expected) {
+        fprintf(stderr, "%s: expected %p, got %p\n",
+                message, (void *)expected, (void *)actual);
+        abort();
+    }
+}
+
+static void
+context_start(struct coroutine_context *from, struct coroutine_context *self)
+{
+#if defined(COROUTINE_SANITIZE_ADDRESS)
+    __sanitizer_finish_switch_fiber(self->fake_stack,
+                                    (const void **)&from->stack_base,
+                                    &from->stack_size);
+#else
+    (void)from;
+    (void)self;
+#endif
+}
+
+static struct coroutine_context *
+transfer(struct coroutine_context *current, struct coroutine_context *target)
+{
+#if defined(COROUTINE_SANITIZE_ADDRESS)
+    __sanitizer_start_switch_fiber(&current->fake_stack,
+                                   target->stack_base, target->stack_size);
+#endif
+
+#if defined(COROUTINE_SANITIZE_THREAD)
+    __tsan_switch_to_fiber(target->tsan_fiber, 0);
+#endif
+
+    struct coroutine_context *from = coroutine_transfer(current, target);
+
+#if defined(COROUTINE_SANITIZE_ADDRESS)
+    __sanitizer_finish_switch_fiber(current->fake_stack, NULL, NULL);
+#endif
+
+    return from;
+}
+
+static COROUTINE
+worker_entry(struct coroutine_context *from, struct coroutine_context *self)
+{
+    context_start(from, self);
+
+    check_context("worker context was entered by", from, &main_context);
+    check_context("worker context received self", self, &worker_context);
+
+    uint32_t state = UINT32_C(0x12345678);
+
+    for (unsigned int iteration = 1; iteration <= TRANSFER_COUNT; iteration++) {
+        state = state * UINT32_C(1664525) + UINT32_C(1013904223);
+        yielded_iteration = iteration;
+        yielded_state = state;
+
+        from = transfer(self, &main_context);
+        check_context("worker context was resumed by", from, &main_context);
+
+        if (yielded_iteration != iteration || yielded_state != state) {
+            fprintf(stderr, "worker local state was not preserved\n");
+            abort();
+        }
+    }
+
+    completed = 1;
+    transfer(self, &main_context);
+    abort();
+}
+
+int
+test_transfer_repeat(void)
+{
+    struct coroutine_stack stack = {0};
+    int result = EXIT_FAILURE;
+
+    if (coroutine_stack_allocate(&stack, STACK_SIZE) != 0) {
+        fprintf(stderr, "failed to allocate coroutine stack\n");
+        return EXIT_FAILURE;
+    }
+
+    yielded_iteration = 0;
+    yielded_state = 0;
+    completed = 0;
+
+    coroutine_initialize_main(&main_context);
+    coroutine_initialize(&worker_context, worker_entry, stack.base, stack.size);
+
+    uint32_t expected_state = UINT32_C(0x12345678);
+
+    for (unsigned int iteration = 1; iteration <= TRANSFER_COUNT; iteration++) {
+        expected_state = expected_state * UINT32_C(1664525) + UINT32_C(1013904223);
+
+        struct coroutine_context *from = transfer(&main_context, &worker_context);
+
+        if (from != &worker_context || yielded_iteration != iteration ||
+            yielded_state != expected_state || completed) {
+            fprintf(stderr, "repeated coroutine transfer failed at iteration %u\n",
+                    iteration);
+            goto finish;
+        }
+    }
+
+    if (transfer(&main_context, &worker_context) != &worker_context || !completed) {
+        fprintf(stderr, "worker context did not complete repeated transfers\n");
+        goto finish;
+    }
+
+    result = EXIT_SUCCESS;
+
+finish:
+    coroutine_destroy(&worker_context);
+    coroutine_destroy(&main_context);
+    coroutine_stack_free(&stack);
+
+    return result;
+}
diff --git a/coroutine/test/test_transfer_repeat.h b/coroutine/test/test_transfer_repeat.h
new file mode 100644
index 00000000000..56c00799378
--- /dev/null
+++ b/coroutine/test/test_transfer_repeat.h
@@ -0,0 +1,3 @@
+#pragma once
+
+int test_transfer_repeat(void);
diff --git a/coroutine/test/test_transfer_return.c b/coroutine/test/test_transfer_return.c
new file mode 100644
index 00000000000..657e00387de
--- /dev/null
+++ b/coroutine/test/test_transfer_return.c
@@ -0,0 +1,142 @@
+#include "ruby/internal/config.h"
+
+#include COROUTINE_H
+
+#include "stack.h"
+#include "test_transfer_return.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#define STACK_SIZE (1024 * 1024)
+
+static struct coroutine_context main_context;
+static struct coroutine_context first_context;
+static struct coroutine_context second_context;
+
+static void
+check_context(const char *message, struct coroutine_context *actual,
+              struct coroutine_context *expected)
+{
+    if (actual != expected) {
+        fprintf(stderr, "%s: expected %p, got %p\n",
+                message, (void *)expected, (void *)actual);
+        abort();
+    }
+}
+
+static void
+context_start(struct coroutine_context *from, struct coroutine_context *self)
+{
+#if defined(COROUTINE_SANITIZE_ADDRESS)
+    __sanitizer_finish_switch_fiber(self->fake_stack,
+                                    (const void **)&from->stack_base,
+                                    &from->stack_size);
+#else
+    (void)from;
+    (void)self;
+#endif
+}
+
+static struct coroutine_context *
+transfer(struct coroutine_context *current, struct coroutine_context *target)
+{
+#if defined(COROUTINE_SANITIZE_ADDRESS)
+    __sanitizer_start_switch_fiber(&current->fake_stack,
+                                   target->stack_base, target->stack_size);
+#endif
+
+#if defined(COROUTINE_SANITIZE_THREAD)
+    __tsan_switch_to_fiber(target->tsan_fiber, 0);
+#endif
+
+    struct coroutine_context *from = coroutine_transfer(current, target);
+
+#if defined(COROUTINE_SANITIZE_ADDRESS)
+    __sanitizer_finish_switch_fiber(current->fake_stack, NULL, NULL);
+#endif
+
+    return from;
+}
+
+static COROUTINE
+second_entry(struct coroutine_context *from, struct coroutine_context *self)
+{
+    context_start(from, self);
+
+    check_context("second context was entered by", from, &first_context);
+    check_context("second context received self", self, &second_context);
+
+    from = transfer(self, &main_context);
+    check_context("second context was resumed by", from, &main_context);
+
+    transfer(self, &first_context);
+    abort();
+}
+
+static COROUTINE
+first_entry(struct coroutine_context *from, struct coroutine_context *self)
+{
+    context_start(from, self);
+
+    check_context("first context was entered by", from, &main_context);
+    check_context("first context received self", self, &first_context);
+
+    from = transfer(self, &second_context);
+    check_context("first context was resumed by", from, &second_context);
+
+    transfer(self, &main_context);
+    abort();
+}
+
+int
+test_transfer_return(void)
+{
+    struct coroutine_stack first_stack = {0};
+    struct coroutine_stack second_stack = {0};
+    int result = EXIT_FAILURE;
+
+    if (coroutine_stack_allocate(&first_stack, STACK_SIZE) != 0 ||
+        coroutine_stack_allocate(&second_stack, STACK_SIZE) != 0) {
+        fprintf(stderr, "failed to allocate coroutine stacks\n");
+        goto finish;
+    }
+
+    coroutine_initialize_main(&main_context);
+    coroutine_initialize(&first_context, first_entry,
+                         first_stack.base, first_stack.size);
+    coroutine_initialize(&second_context, second_entry,
+                         second_stack.base, second_stack.size);
+
+    result = EXIT_SUCCESS;
+
+    /* The original target is first_context, but second_context resumes us. */
+    struct coroutine_context *from = transfer(&main_context, &first_context);
+
+    if (from != &second_context) {
+        fprintf(stderr,
+                "coroutine_transfer returned %p, expected actual resumer %p\n",
+                (void *)from, (void *)&second_context);
+        result = EXIT_FAILURE;
+    }
+
+    /* Resume second_context, which resumes first_context, which resumes us. */
+    from = transfer(&main_context, &second_context);
+
+    if (from != &first_context) {
+        fprintf(stderr,
+                "coroutine_transfer returned %p, expected actual resumer %p\n",
+                (void *)from, (void *)&first_context);
+        result = EXIT_FAILURE;
+    }
+
+    coroutine_destroy(&first_context);
+    coroutine_destroy(&second_context);
+    coroutine_destroy(&main_context);
+
+finish:
+    coroutine_stack_free(&first_stack);
+    coroutine_stack_free(&second_stack);
+
+    return result;
+}
diff --git a/coroutine/test/test_transfer_return.h b/coroutine/test/test_transfer_return.h
new file mode 100644
index 00000000000..228d611cde3
--- /dev/null
+++ b/coroutine/test/test_transfer_return.h
@@ -0,0 +1,3 @@
+#pragma once
+
+int test_transfer_return(void);
diff --git a/depend b/depend
index a18eebe3fa9..4099bd57bac 100644
--- a/depend
+++ b/depend
@@ -55,6 +55,11 @@ compile.$(OBJEXT): {$(VPATH)}compile.c
 complex.$(OBJEXT): {$(VPATH)}complex.c
 concurrent_set.$(OBJEXT): {$(VPATH)}concurrent_set.c
 cont.$(OBJEXT): {$(VPATH)}cont.c
+coroutine-main.$(OBJEXT): {$(VPATH)}coroutine/test/main.c
+coroutine-stack.$(OBJEXT): {$(VPATH)}coroutine/test/stack.c
+coroutine-test_initialize_destroy.$(OBJEXT): {$(VPATH)}coroutine/test/test_initialize_destroy.c
+coroutine-test_transfer_repeat.$(OBJEXT): {$(VPATH)}coroutine/test/test_transfer_repeat.c
+coroutine-test_transfer_return.$(OBJEXT): {$(VPATH)}coroutine/test/test_transfer_return.c
 debug.$(OBJEXT): {$(VPATH)}debug.c
 debug_counter.$(OBJEXT): {$(VPATH)}debug_counter.c
 dir.$(OBJEXT): {$(VPATH)}dir.c
diff --git a/template/Makefile.in b/template/Makefile.in
index a519dfb858c..68e53e379b4 100644
--- a/template/Makefile.in
+++ b/template/Makefile.in
@@ -185,6 +185,8 @@ BOOTSTRAPRUBY_FAKE = $(yes_baseruby:yes=$(arch)-fake.rb)
 COROUTINE_H = @X_COROUTINE_H@
 COROUTINE_OBJ = $(COROUTINE_H:.h=.$(OBJEXT))
 COROUTINE_SRC = @X_COROUTINE_SRC@
+COROUTINE_TEST_LINK = $(CC) $(EXE_LDFLAGS) $(XLDFLAGS) $(COROUTINE_TEST_OBJS) $(COROUTINE_OBJ) $(MAINLIBS) $(OUTFLAG)$(COROUTINE_TEST)
+COROUTINE_TEST_RUN = ./$(COROUTINE_TEST)
 
 #### End of system configuration section. ####
 
diff --git a/thread_sched.h b/thread_sched.h
index e56f5d7dd19..2b38f08a71a 100644
--- a/thread_sched.h
+++ b/thread_sched.h
@@ -161,8 +161,8 @@ struct rb_native_thread {
     bool retiring;
 
     // A terminating coroutine records its context here before its final
-    // transfer; this nt's loop reclaims it. (Not via coroutine_transfer()'s
-    // return value: its meaning differs between the amd64 asm and ucontext.)
+    // transfer; this nt's loop reclaims it. coroutine_transfer() cannot be
+    // used because a terminating coroutine never resumes to return a value.
     struct coroutine_context *dead_co;
 };
 
diff --git a/win32/Makefile.sub b/win32/Makefile.sub
index ccc3e918f50..897964ab028 100644
--- a/win32/Makefile.sub
+++ b/win32/Makefile.sub
@@ -344,6 +344,8 @@ COROUTINE_SRC = $(COROUTINE_OBJ:.obj=.asm)
 !error copy coroutine has been replaced with pthread implementation at 42130a64f02294dc8025af3a51bda518c67ab33d
 !endif
 COROUTINE_H = $(COROUTINE_OBJ:.obj=.h)
+COROUTINE_TEST_LINK = $(CC) $(COROUTINE_TEST_OBJS) $(COROUTINE_OBJ) $(MAINLIBS) $(OUTFLAG)$(COROUTINE_TEST) -link $(LDFLAGS) $(XLDFLAGS)
+COROUTINE_TEST_RUN = .\$(COROUTINE_TEST)
 
 ARFLAGS = -machine:$(MACHINE) -out:
 LD = $(CC)