ARM syscalls.c: Tidy up formatting.

ports/arm/syscalls.c

@@ -1,4 +1,45 @@
-/* Mostly based on code from http://balau82.wordpress.com */
+/*
+ * Copyright (c) 2013, Kelvin Lawson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. No personal names or organizations' names associated with the
+ *    Atomthreads project may be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE ATOMTHREADS PROJECT AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+
+/** 
+ * \file
+ * Syscalls implementation for stdio and heap management.
+ *
+ *
+ * Simple implementation of syscalls.c for ARM compiler toolchains built
+ * without newlib. Allows usage of printf() and friends as well as heap
+ * allocation.
+ *
+ * Mostly based on code from http://balau82.wordpress.com
+ *
+ */
 
 #include <sys/stat.h>
 
@@ -11,8 +52,10 @@ enum {
 #define UART_DR(baseaddr) (*(unsigned int *)(baseaddr))
 #define UART_FR(baseaddr) (*(((unsigned int *)(baseaddr))+6))
 
+
 /** 
- * Define all functions as weak in case the compiler toolchain provides them
+ * Define all functions as weak so that the functions in this file will
+ * only be used if the compiler toolchain doesn't already provide them.
  */
 extern int _close(int file) __attribute__((weak));
 extern int _fstat(int file, struct stat *st) __attribute__((weak));
@@ -24,63 +67,143 @@ extern caddr_t _sbrk(int incr) __attribute__((weak));
 extern int _write(int file, char *ptr, int len) __attribute__((weak));
 
 
-int _close(int file) { return -1; }
-
-int _fstat(int file, struct stat *st) {
- st->st_mode = S_IFCHR;
- return 0;
+/**
+ * \b _close
+ *
+ * Simple stub implementation.
+ *
+ */
+int _close(int file)
+{
+    return -1;
 }
 
-int _isatty(int file) { return 1; }
 
-int _lseek(int file, int ptr, int dir) { return 0; }
-
-int _open(const char *name, int flags, int mode) { return -1; }
-
-int _read(int file, char *ptr, int len) {
- int todo;
- if(len == 0)
-  return 0;
- while(UART_FR(UART0_ADDR) & UART_FR_RXFE)
-  ;
- *ptr++ = UART_DR(UART0_ADDR);
- for(todo = 1; todo < len; todo++) {
-  if(UART_FR(UART0_ADDR) & UART_FR_RXFE) {
-   break;
- }
- *ptr++ = UART_DR(UART0_ADDR);
- }
- return todo;
+/**
+ * \b _fstat
+ *
+ * Simple stub implementation.
+ *
+ */
+int _fstat(int file, struct stat *st)
+{
+    st->st_mode = S_IFCHR;
+    return 0;
 }
 
-char *heap_end = 0;
-caddr_t _sbrk(int incr) {
- extern char end; /* Defined by the linker */
- extern char heap_top; /* Defined by the linker */
- static char *heap_end;
+
+/**
+ * \b _isatty
+ *
+ * Simple stub implementation.
+ *
+ */
+int _isatty(int file)
+{
+    return 1;
+}
+
+
+/**
+ * \b _lseek
+ *
+ * Simple stub implementation.
+ *
+ */
+int _lseek(int file, int ptr, int dir)
+{
+    return 0;
+}
+
+
+/**
+ * \b _open
+ *
+ * Simple stub implementation.
+ *
+ */
+int _open(const char *name, int flags, int mode)
+{
+    return -1;
+}
+
+
+/**
+ * \b _read
+ *
+ * Simple stub implementation.
+ *
+ */
+int _read(int file, char *ptr, int len)
+{
+    int todo;
+
+    if(len == 0)
+        return 0;
+
+    while(UART_FR(UART0_ADDR) & UART_FR_RXFE)
+        ;
+
+    *ptr++ = UART_DR(UART0_ADDR);
+    for (todo = 1; todo < len; todo++)
+    {
+        if(UART_FR(UART0_ADDR) & UART_FR_RXFE)
+        {
+            break;
+        }
+        *ptr++ = UART_DR(UART0_ADDR);
+    }
+    return todo;
+}
+
+
+/**
+ * \b _write
+ *
+ * Simple stub implementation.
+ *
+ */
+int _write(int file, char *ptr, int len)
+{
+    int todo;
+
+    for (todo = 0; todo < len; todo++)
+    {
+        while(UART_FR(UART0_ADDR) & UART_FR_TXFF)
+            ;
+        UART_DR(UART0_ADDR) = *ptr++;
+    }
+
+    return len;
+}
+
+
+/**
+ * \b _sbrk
+ *
+ * Simple stub implementation.
+ *
+ */
+caddr_t _sbrk(int incr)
+{
+ extern char end;          /* Defined by the linker */
+ extern char heap_top;     /* Defined by the linker */
+ static char *heap_end = 0;
  char *prev_heap_end;
 
- if (heap_end == 0) {
-  heap_end = &end;
- }
- prev_heap_end = heap_end;
+    if (heap_end == 0)
+    {
+        heap_end = &end;
+    }
+    prev_heap_end = heap_end;
 
- if (heap_end + incr > &heap_top) {
-  /* Heap and stack collision */
-  return (caddr_t)0;
- }
+    if (heap_end + incr > &heap_top)
+    {
+        /* Heap and stack collision */
+        return (caddr_t)0;
+    }
 
- heap_end += incr;
- return (caddr_t) prev_heap_end;
- }
+    heap_end += incr;
+    return (caddr_t)prev_heap_end;
+}
 
-int _write(int file, char *ptr, int len) {
- int todo;
-
- for (todo = 0; todo < len; todo++) {
-  while(UART_FR(UART0_ADDR) & UART_FR_TXFF)
-   ;
-  UART_DR(UART0_ADDR) = *ptr++;
- }
- return len;
- }