From 4af3f2e5e87b397b3b135a03d87cb4bbcb00374d Mon Sep 17 00:00:00 2001
From: Terraneo Federico <fede.tft@miosix.org>
Date: Sat, 7 Sep 2019 19:11:18 +0200
Subject: [PATCH] Miosix support for libatomic
---
Makefile | 11 +++++--
.../libstdcpp_integration.cpp | 30 +++++++++++++++++++
2 files changed, 39 insertions(+), 2 deletions(-)
diff --git a/Makefile b/Makefile
index 89b7b3bd..c7f35af5 100644
--- a/Makefile
+++ b/Makefile
@@ -56,8 +56,15 @@ AFLAGS := $(AFLAGS_BASE)
LFLAGS := $(LFLAGS_BASE)
DFLAGS := -MMD -MP
-LINK_LIBS := $(LIBS) -L$(KPATH) -Wl,--start-group -lmiosix -lstdc++ -lc \
- -lm -lgcc -Wl,--end-group
+## libmiosix.a is among stdlibs because needs to be within start/end group
+STDLIBS := -lmiosix -lstdc++ -lc -lm -lgcc
+
+GCCMAJOR := $(shell $(CC) --version | perl -e '$$_=<>;/\(GCC\) (\d+)/;print "$$1"')
+ifneq ($(GCCMAJOR),4)
+ STDLIBS += -latomic
+endif
+
+LINK_LIBS := $(LIBS) -L$(KPATH) -Wl,--start-group $(STDLIBS) -Wl,--end-group
all: all-recursive main
diff --git a/miosix/stdlib_integration/libstdcpp_integration.cpp b/miosix/stdlib_integration/libstdcpp_integration.cpp
index 785f4706..98d26ac5 100644
--- a/miosix/stdlib_integration/libstdcpp_integration.cpp
+++ b/miosix/stdlib_integration/libstdcpp_integration.cpp
@@ -303,3 +303,33 @@ extern "C" void __cxa_guard_abort(__guard *g) noexcept
}
} //namespace __cxxabiv1
+
+//
+// libatomic support, to provide thread safe atomic operation fallbacks
+// ====================================================================
+
+// Not using the fast version, as these may be used before the kernel is started
+
+extern "C" unsigned int libat_quick_lock_n(void *ptr)
+{
+ miosix::disableInterrupts();
+ return 0;
+}
+
+extern "C" void libat_quick_unlock_n(void *ptr, unsigned int token)
+{
+ miosix::enableInterrupts();
+}
+
+// These are to implement "heavy" atomic operations, which are not used in
+// libstdc++. For now let's keep them disbaled.
+
+// extern "C" void libat_lock_n(void *ptr, size_t n)
+// {
+// miosix::pauseKernel();
+// }
+//
+// extern "C" void libat_unlock_n(void *ptr, size_t n)
+// {
+// miosix::restartKernel();
+// }
--
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