Diff: src/kernel/syscalls.c

Revision:

0:ccdea31d8eba

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/kernel/syscalls.c	Fri Aug 23 16:43:44 2019 +0000
@@ -0,0 +1,113 @@
+#include <stm32f4xx.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include "drivers/uart.h"
+
+#define STACK_POINTER (__get_MSP())
+#define UART_AUTO_ECHO
+
+
+int _close(int file)
+{
+    UNUSED(file);
+    return -1;
+}
+
+
+int _fstat(int file, struct stat *st)
+{
+    UNUSED(file);
+    st->st_mode = S_IFCHR;
+    return 0;
+}
+
+
+int _isatty(int file)
+{
+    switch(file) {
+    case 1: // stdio
+    case 2: // stderr
+    return 1;
+
+    default: return 0;
+    }
+}
+
+
+int _lseek(int file, int ptr, int dir)
+{
+    UNUSED(file); UNUSED(ptr); UNUSED(dir);
+    return 0;
+}
+
+
+int _open(const char *name, int flags, int mode)
+{
+    UNUSED(name); UNUSED(flags); UNUSED(mode);
+    return -1;
+}
+
+
+int _read(int file, char *ptr, int len)
+{
+    UNUSED(file);
+    int i;
+    for (i = 0; i < len; i++) {
+        ptr[i] = _uart_getc();
+        #ifdef UART_AUTO_ECHO
+        _uart_putc(ptr[i]);
+        #endif
+        /* Return partial buffer if we get EOL */
+        if ('\r' == ptr[i]) {
+            ++i;
+            ptr[i] = '\n';
+            return i;
+        }
+    }
+
+    ptr[i-1] = '\r';
+    ptr[i] = '\n';
+    return  i;
+}
+
+
+caddr_t _sbrk(int incr)
+{
+    extern char _end;		/* Defined by the linker */
+    static char *heap_end;
+    char *prev_heap_end;
+
+    if (heap_end == 0) {
+        heap_end = &_end;
+    }
+    prev_heap_end = heap_end;
+    if ((unsigned)(heap_end + incr) > STACK_POINTER) {
+        /* Heap and stack collision */
+        return (caddr_t)0;
+    }
+
+    heap_end += incr;
+    return (caddr_t) prev_heap_end;
+}
+
+
+int _write(int file, char *ptr, int len)
+{
+    if (!isatty(file)) {
+        return BSP_UARTx_transmit((uint8_t*)ptr, len) == 0 ? len : 0;
+    }
+
+    int todo;
+    for (todo = 0; todo < len; todo++) {
+        const char c = *ptr++;
+        if (c == '\n') BSP_UARTx_transmit((uint8_t*)&(char){'\r'}, 1);
+        if (BSP_UARTx_transmit((uint8_t*)&c, 1) != 0) break;
+    }
+
+    return todo;
+}
+
+
+void _init(void) {}
+