meta: update build instructions

This is because all of these headers are included in direct style with
no subfolder so we need them to be in a quite public `include/` folder.
The Makefile installs in `include/openlibm/` but this only works with
extra `-I` flags that are quite annoying to enforce.

With this change, the only OpenLibm headers that are installed are named
`openlibm_*.h`, which is sufficient in terms of namespacing.

Also add a symlink libm.a -> libopenlibm.a.

Makefile

@@ -93,6 +93,9 @@ install-static: libopenlibm.a
 	mkdir -p $(DESTDIR)$(libdir)
 	cp -RpP -f libopenlibm.a $(DESTDIR)$(libdir)/
 
+install-static-superh: install-static
+	ln -sf libopenlibm.a $(DESTDIR)$(libdir)/libm.a
+
 install-shared: libopenlibm.$(OLM_MAJOR_MINOR_SHLIB_EXT)
 	mkdir -p $(DESTDIR)$(shlibdir)
 	cp -RpP -f libopenlibm.*$(SHLIB_EXT)* $(DESTDIR)$(shlibdir)/
@@ -106,4 +109,15 @@ install-headers:
 	cp -RpP -f include/*.h $(DESTDIR)$(includedir)/openlibm
 	cp -RpP -f src/*.h $(DESTDIR)$(includedir)/openlibm
 
-install: install-static install-shared install-pkgconfig install-headers
+install-headers-superh:
+	mkdir -p $(DESTDIR)$(includedir)
+	cp -RpP -f                        \
+	  include/openlibm.h              \
+	  include/openlibm_complex.h      \
+	  include/openlibm_defs.h         \
+	  include/openlibm_fenv.h         \
+	  include/openlibm_fenv_sh3eb.h   \
+	  include/openlibm_math.h         \
+	  $(DESTDIR)$(includedir)
+
+install: install-static install-shared install-pkgconfig

README.md

@@ -1,57 +1,60 @@
 # Soft-FP sh3eb port of OpenLibm
 
-This is a fork of [OpenLibm](https://github.com/JuliaMath/openlibm) with
-support for the sh3eb architecture, intended for add-in programming on fx-9860G
-and fx-CG 50.
+This is a fork of [OpenLibm](https://github.com/JuliaMath/openlibm) with support for the sh3eb architecture, intended for add-in programming on SuperH CASIO calculators.
 
 ## Installing with GiteaPC
 
-This library can be installed automatically with [GiteaPC](https://gitea.planet-casio.com/Lephenixnoir/GiteaPC).
+This library can be installed automatically as part of the fxSDK with [GiteaPC](https://gitea.planet-casio.com/Lephenixnoir/GiteaPC):
 
-```
+```bash
 % giteapc install Lephenixnoir/OpenLibm
 ```
 
 ## Building manually
 
-You will need a GCC toolchain built with `--target=sh3eb-elf`, such as the
-`sh-elf-gcc` commonly used on Planète Casio.
+You will need a GCC toolchain built with `--target=sh3eb-elf`, such as the [`sh-elf-gcc`](https://gitea.planet-casio.com/Lephenixnoir/sh-elf-gcc) commonly used on Planète Casio.
 
-First locate the compiler's install directory. This is normally the
-`lib/gcc/sh3eb-elf/<version>/` folder inside the install path of the compiler.
+You can install directly in the internal folder of your compiler, or somewhere else if you have a more detailed setup.
 
-```
-% PREFIX=$(sh-elf-gcc --print-search-dirs | grep install | sed 's/install: //')
+```bash
+# Example 1: Use the compiler's internal folder
+% COMPILER_DIR="$(sh-elf-gcc --print-file-name=.)"
+% LIBDIR="$COMPILER_DIR"
+% INCDIR="$COMPILER_DIR/include"
+# Example 2: Using the fxSDK's custom setup
+% LIBDIR="$(fxsdk path lib)"
+% INCDIR="$(fxsdk path include)"
 ```
 
-You can then build and install the static `libopenlibm.a` archive and the headers.
+You can then build and install the static library and the headers.
 
-```
-% make USEGCC=1 TOOLPREFIX=sh-elf- AR=sh-elf-ar CC=sh-elf-gcc libdir="$PREFIX" includedir="$PREFIX/include" install-static install-headers
+```bash
+% make USEGCC=1 TOOLPREFIX=sh-elf- AR=sh-elf-ar CC=sh-elf-gcc \
+    libdir="$LIBDIR" includedir="$INCDIR" \
+    install-static-superh install-headers-superh
 ```
 
-## Using in a Makefile-based add-in
+The `-superh` targets differ from the the normal targets in the following ways:
 
-Link with `-lopenlibm` as you would do with `-lm`. Since OpenLibm headers
-reference themselves by file name (`#include <openlibm_complex.h>`) even though
-they are installed in a subfolder, you need a `-I` flag:
+* `install-static-superh` also creates a symlink `libm.a -> libopenlibm.a`.
+* `install-headers-superh` installs directly in `$LIBDIR` instead of `$LIBDIR/openlibm` since OpenLibm headers reference each other without that prefix and enforcing the correct `-I` in every project is quite painful. In addition, it skips internal and non-SuperH headers.
+
+## Using the library
+
+Include the headers `<openlibm_complex.h>`, `<openlibm_fenv.h>` and `<openlibm_math.h>`. Or, if you are using a suitable libc like [fxlibc](https://gitea.planet-casio.com/Vhex-Kernel-Core/fxlibc/), include directly the standard headers `<complex.h>`, `<fenv.h>` and `<math.h>`.
+
+Link with `-lm`. In a Makefile, update your `LDFLAGS`:
 
 ```
-CFLAGS += -I $(shell sh-elf-gcc -print-file-name=include/openlibm)
-LDFLAGS += -lopenlibm
+LDFLAGS += -lm
 ```
 
-## Using in a CMake-based add-in
+In CMake, use [`target_link_libraries()`](https://cmake.org/cmake/help/latest/command/target_link_libraries.html):
 
-When using CMake with the fxSDK, add the include folder and library like this.
-
-```
-target_include_directories(<TARGET> PRIVATE "${FXSDK_COMPILER_INSTALL}/include/openlibm")
-target_link_libraries(<TARGET> -lopenlibm)
+```cmake
+target_link_libraries(<TARGET> PUBLIC -lm)
 ```
 
 ## README and Licensing
 
-See the original README file in [README-OpenLibm.md](README-OpenLibm.md).
-OpenLibm contains code covered by various licenses, see
-[LICENSE.md](LICENSE.md).
+See the original README file in [README-OpenLibm.md](README-OpenLibm.md). OpenLibm contains code covered by various licenses, see [LICENSE.md](LICENSE.md).

giteapc.make

@@ -1,17 +1,22 @@
-# giteapc: version=1 depends=Lephenixnoir/sh-elf-gcc
+# giteapc: version=1 depends=Lephenixnoir/fxsdk,Lephenixnoir/sh-elf-gcc
 
 -include giteapc-config.make
 
-PREFIX ?= $(shell sh-elf-gcc --print-search-dirs | grep install | sed 's/install: //')
+# Use the fxSDK's default paths unless specified otherwise on the command line
+LIBDIR ?= $(shell fxsdk path lib)
+INCDIR ?= $(shell fxsdk path include)
+
+FLAGS := USEGCC=1 TOOLPREFIX=sh-elf- CC=sh-elf-gcc AR=sh-elf-ar \
+         libdir="$(LIBDIR)" includedir="$(INCDIR)"
 
 configure:
 	@ true
 
 build:
-	@ make USEGCC=1 TOOLPREFIX=sh-elf- CC=sh-elf-gcc AR=sh-elf-ar libdir="$(PREFIX)" includedir="$(PREFIX)/include"
+	@ make $(FLAGS)
 
 install:
-	@ make USEGCC=1 TOOLPREFIX=sh-elf- CC=sh-elf-gcc AR=sh-elf-ar libdir="$(PREFIX)" includedir="$(PREFIX)/include" install-static install-headers
+	@ make $(FLAGS) install-static-superh install-headers-superh
 
 uninstall:
 	@ echo "uninstall not supported for OpenLibm, skipping"

include/openlibm_fenv_sh3eb.h

@@ -30,7 +30,6 @@
 #define	_FENV_H_
 
 #include <stdint.h>
-#include "cdefs-compat.h"
 
 #ifndef	__fenv_static
 #define	__fenv_static	static
@@ -57,7 +56,10 @@ typedef	uint32_t	fexcept_t;
 #define	FE_DOWNWARD	0x0003
 #define	_ROUND_MASK	(FE_TONEAREST | FE_DOWNWARD | \
 			 FE_UPWARD | FE_TOWARDZERO)
-__BEGIN_DECLS
+
+#ifdef __cplusplus
+extern "C" {
+#endif
 
 /* Default floating-point environment */
 extern const fenv_t	__fe_dfl_env;
@@ -89,6 +91,8 @@ int fegetexcept(void);
 
 #endif /* __BSD_VISIBLE */
 
-__END_DECLS
+#ifdef __cplusplus
+}
+#endif
 
 #endif	/* !_FENV_H_ */