Remove CS3-style initialization.

Remove libcs3-related bits from support/ld. Break them out into
libmaple proper and Wirish as appropriate: vector table definition and
ISR declarations go into libmaple proper, and startup code goes into
Wirish. Vector table symbols are included into common.inc from an
STM32 family-specific directory under support/ld/stm32.

This is a combination of 5 commits. Individual commit messages follow:

libcs3_stm32_src: Don't depend on cs3.h.

So we can use the existing toolchain.

Move ISR decls/vector table into libmaple proper.

This allows us to configure the vector table on a per-family basis.

- Move
        support/ld/libcs3_stm32_src/stm32_isrs.S
                                    stm32_vector_table.S
  to
        libmaple/stm32f1/isrs_performance.S
                         vector_table_performance.S,
  respectively.

  The directory libmaple/stm32f1/ is intended to hold all
  STM32F1-specific code within libmaple. Obviously, there's a lot of
  work to do before this becomes true.

- support/ld/libcs3_stm32_src/Makefile: Don't try to compile
  stm32_isrs.S and stm32_vector_table.S anymore.

- Add libmaple/stm32f1/rules.mk to include these new files in the
  standard libmaple build.

- support/make/target-config.mk: Add LIBMAPLE_MODULE_FAMILY, which
  selects a directory to use as a family-specific libmaple
  submodule.

- Makefile: Add LIBMAPLE_MODULE_FAMILY to LIBMAPLE_MODULES.

Remove support/ld/libcs3_stm32_src and derived object files.

From support/ld/libcs3_stm32_src, move start.S and start_c.c into
Wirish. Modify wirish/rules.mk accordingly.

Delete support/ld/libcs3_stm32_*_density.a. These are no longer
necessary, as the relevant objects are included in the standard Wirish
build. Remove the GROUP statements from the board linker scripts
accordingly.

Remove SEARCH_DIR(.) from common.inc; it's no longer necessary. Also
fix up some comments that are now out of date.

wirish/start_c.c: Don't use CS3-style memory initialization.

Switch memory initialization to a simpler style of initializing .data
if necessary, then zeroing .bss. Initializing .data is only necessary
during Flash builds, since during RAM builds, LOADADDR(.data) ==
ADDR(.data).

This makes libmaple completely incompatible with the CS3 startup
sequence. Subsequent commits will clean up the namespace to reflect
that fact.

Signed-off-by: Marti Bolivar <mbolivar@leaflabs.com>

3 files changed, 97 insertions, 2 deletions

diff --git a/wirish/rules.mk b/wirish/rules.mk
index 6aa0904..1bf6245 100644
--- a/wirish/rules.mk
+++ b/wirish/rules.mk
@@ -12,8 +12,9 @@ WIRISH_INCLUDES := -I$(d) -I$(d)/comm -I$(d)/boards
 CFLAGS_$(d) := $(WIRISH_INCLUDES) $(LIBMAPLE_INCLUDES)
 
 # Local rules and targets
-cSRCS_$(d) :=  
 
+sSRCS_$(d) := start.S
+cSRCS_$(d) := start_c.c
 cppSRCS_$(d) := wirish_math.cpp		 \
                 Print.cpp		 \
 		boards.cpp               \
@@ -34,10 +35,12 @@ cppSRCS_$(d) := wirish_math.cpp		 \
 		ext_interrupts.cpp	 \
 		wirish_digital.cpp
 
+sFILES_$(d)   := $(sSRCS_$(d):%=$(d)/%)
 cFILES_$(d)   := $(cSRCS_$(d):%=$(d)/%)
 cppFILES_$(d) := $(cppSRCS_$(d):%=$(d)/%)
 
-OBJS_$(d)     := $(cFILES_$(d):%.c=$(BUILD_PATH)/%.o) \
+OBJS_$(d)     := $(sFILES_$(d):%.S=$(BUILD_PATH)/%.o) \
+                 $(cFILES_$(d):%.c=$(BUILD_PATH)/%.o) \
                  $(cppFILES_$(d):%.cpp=$(BUILD_PATH)/%.o)
 DEPS_$(d)     := $(OBJS_$(d):%.o=%.d)
 
diff --git a/wirish/start.S b/wirish/start.S
new file mode 100644
index 0000000..4d1d405
--- /dev/null
+++ b/wirish/start.S
@@ -0,0 +1,27 @@
+/*
+ * The authors hereby grant permission to use, copy, modify, distribute,
+ * and license this software and its documentation for any purpose, provided
+ * that existing copyright notices are retained in all copies and that this
+ * notice is included verbatim in any distributions. No written agreement,
+ * license, or royalty fee is required for any of the authorized uses.
+ * Modifications to this software may be copyrighted by their authors
+ * and need not follow the licensing terms described here, provided that
+ * the new terms are clearly indicated on the first page of each file where
+ * they apply.
+ */
+
+	.text
+	.code 16
+	.thumb_func
+
+	.globl _start
+	.type _start, %function
+_start:
+	.fnstart
+	ldr	r1,=__cs3_stack
+	mov	sp,r1
+	ldr	r1,=__cs3_start_c
+	bx	r1
+	.pool
+	.cantunwind
+	.fnend
diff --git a/wirish/start_c.c b/wirish/start_c.c
new file mode 100644
index 0000000..cb96fc5
--- /dev/null
+++ b/wirish/start_c.c
@@ -0,0 +1,65 @@
+/* CS3 start_c routine.
+ *
+ * Copyright (c) 2006, 2007 CodeSourcery Inc
+ *
+ * The authors hereby grant permission to use, copy, modify, distribute,
+ * and license this software and its documentation for any purpose, provided
+ * that existing copyright notices are retained in all copies and that this
+ * notice is included verbatim in any distributions. No written agreement,
+ * license, or royalty fee is required for any of the authorized uses.
+ * Modifications to this software may be copyrighted by their authors
+ * and need not follow the licensing terms described here, provided that
+ * the new terms are clearly indicated on the first page of each file where
+ * they apply.
+ */
+
+#include <stddef.h>
+
+extern void __libc_init_array (void);
+
+extern int main (int, char **, char **);
+
+extern void exit (int) __attribute__ ((noreturn, weak));
+
+extern char _data, _edata;
+extern char _bss, _ebss;
+
+struct rom_img_cfg {
+  long long *img_start;
+};
+
+extern char _lm_rom_img_cfgp;
+
+void  __attribute__ ((noreturn))
+__cs3_start_c (void)
+{
+  struct rom_img_cfg *img_cfg = (struct rom_img_cfg*)&_lm_rom_img_cfgp;
+  long long *src;
+  long long *dst;
+  int exit_code;
+
+  /* Initialize .data, if necessary. */
+  src = img_cfg->img_start;
+  dst = (long long*)&_data;
+  if (src != dst) {
+    while (dst < (long long*)&_edata) {
+      *dst++ = *src++;
+    }
+  }
+
+  /* Zero .bss. */
+  dst = (long long*)&_bss;
+  while (dst < (long long*)&_ebss) {
+    *dst++ = 0;
+  }
+
+  /* Run initializers.  */
+  __libc_init_array ();
+
+  exit_code = main (0, NULL, NULL);
+  if (exit)
+    exit (exit_code);
+  /* If exit is NULL, make sure we don't return. */
+  for (;;)
+    continue;
+}