add exercise of lab5 spoc discussion

related_info/lab5/lab5-spoc-discuss/user/libs/initcode.S

@@ -0,0 +1,14 @@
+.text
+.globl _start
+_start:
+    # set ebp for backtrace
+    movl $0x0, %ebp
+
+    # move down the esp register
+    # since it may cause page fault in backtrace
+    subl $0x20, %esp
+
+    # call user-program function
+    call umain
+1:  jmp 1b
+

related_info/lab5/lab5-spoc-discuss/user/libs/panic.c

@@ -0,0 +1,28 @@
+#include <defs.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <ulib.h>
+#include <error.h>
+
+void
+__panic(const char *file, int line, const char *fmt, ...) {
+    // print the 'message'
+    va_list ap;
+    va_start(ap, fmt);
+    cprintf("user panic at %s:%d:\n    ", file, line);
+    vcprintf(fmt, ap);
+    cprintf("\n");
+    va_end(ap);
+    exit(-E_PANIC);
+}
+
+void
+__warn(const char *file, int line, const char *fmt, ...) {
+    va_list ap;
+    va_start(ap, fmt);
+    cprintf("user warning at %s:%d:\n    ", file, line);
+    vcprintf(fmt, ap);
+    cprintf("\n");
+    va_end(ap);
+}
+

related_info/lab5/lab5-spoc-discuss/user/libs/stdio.c

@@ -0,0 +1,62 @@
+#include <defs.h>
+#include <stdio.h>
+#include <syscall.h>
+
+/* *
+ * cputch - writes a single character @c to stdout, and it will
+ * increace the value of counter pointed by @cnt.
+ * */
+static void
+cputch(int c, int *cnt) {
+    sys_putc(c);
+    (*cnt) ++;
+}
+
+/* *
+ * vcprintf - format a string and writes it to stdout
+ *
+ * The return value is the number of characters which would be
+ * written to stdout.
+ *
+ * Call this function if you are already dealing with a va_list.
+ * Or you probably want cprintf() instead.
+ * */
+int
+vcprintf(const char *fmt, va_list ap) {
+    int cnt = 0;
+    vprintfmt((void*)cputch, &cnt, fmt, ap);
+    return cnt;
+}
+
+/* *
+ * cprintf - formats a string and writes it to stdout
+ *
+ * The return value is the number of characters which would be
+ * written to stdout.
+ * */
+int
+cprintf(const char *fmt, ...) {
+    va_list ap;
+
+    va_start(ap, fmt);
+    int cnt = vcprintf(fmt, ap);
+    va_end(ap);
+
+    return cnt;
+}
+
+/* *
+ * cputs- writes the string pointed by @str to stdout and
+ * appends a newline character.
+ * */
+int
+cputs(const char *str) {
+    int cnt = 0;
+    char c;
+    while ((c = *str ++) != '\0') {
+        cputch(c, &cnt);
+    }
+    cputch('\n', &cnt);
+    return cnt;
+}
+

related_info/lab5/lab5-spoc-discuss/user/libs/syscall.c

@@ -0,0 +1,72 @@
+#include <defs.h>
+#include <unistd.h>
+#include <stdarg.h>
+#include <syscall.h>
+
+#define MAX_ARGS            5
+
+static inline int
+syscall(int num, ...) {
+    va_list ap;
+    va_start(ap, num);
+    uint32_t a[MAX_ARGS];
+    int i, ret;
+    for (i = 0; i < MAX_ARGS; i ++) {
+        a[i] = va_arg(ap, uint32_t);
+    }
+    va_end(ap);
+
+    asm volatile (
+        "int %1;"
+        : "=a" (ret)
+        : "i" (T_SYSCALL),
+          "a" (num),
+          "d" (a[0]),
+          "c" (a[1]),
+          "b" (a[2]),
+          "D" (a[3]),
+          "S" (a[4])
+        : "cc", "memory");
+    return ret;
+}
+
+int
+sys_exit(int error_code) {
+    return syscall(SYS_exit, error_code);
+}
+
+int
+sys_fork(void) {
+    return syscall(SYS_fork);
+}
+
+int
+sys_wait(int pid, int *store) {
+    return syscall(SYS_wait, pid, store);
+}
+
+int
+sys_yield(void) {
+    return syscall(SYS_yield);
+}
+
+int
+sys_kill(int pid) {
+    return syscall(SYS_kill, pid);
+}
+
+int
+sys_getpid(void) {
+    return syscall(SYS_getpid);
+}
+
+int
+sys_putc(int c) {
+    return syscall(SYS_putc, c);
+}
+
+int
+sys_pgdir(void) {
+    return syscall(SYS_pgdir);
+}
+

related_info/lab5/lab5-spoc-discuss/user/libs/syscall.h

@@ -0,0 +1,14 @@
+#ifndef __USER_LIBS_SYSCALL_H__
+#define __USER_LIBS_SYSCALL_H__
+
+int sys_exit(int error_code);
+int sys_fork(void);
+int sys_wait(int pid, int *store);
+int sys_yield(void);
+int sys_kill(int pid);
+int sys_getpid(void);
+int sys_putc(int c);
+int sys_pgdir(void);
+
+#endif /* !__USER_LIBS_SYSCALL_H__ */
+

related_info/lab5/lab5-spoc-discuss/user/libs/ulib.c

@@ -0,0 +1,48 @@
+#include <defs.h>
+#include <syscall.h>
+#include <stdio.h>
+#include <ulib.h>
+
+void
+exit(int error_code) {
+    sys_exit(error_code);
+    cprintf("BUG: exit failed.\n");
+    while (1);
+}
+
+int
+fork(void) {
+    return sys_fork();
+}
+
+int
+wait(void) {
+    return sys_wait(0, NULL);
+}
+
+int
+waitpid(int pid, int *store) {
+    return sys_wait(pid, store);
+}
+
+void
+yield(void) {
+    sys_yield();
+}
+
+int
+kill(int pid) {
+    return sys_kill(pid);
+}
+
+int
+getpid(void) {
+    return sys_getpid();
+}
+
+//print_pgdir - print the PDT&PT
+void
+print_pgdir(void) {
+    sys_pgdir();
+}
+

related_info/lab5/lab5-spoc-discuss/user/libs/ulib.h

@@ -0,0 +1,36 @@
+#ifndef __USER_LIBS_ULIB_H__
+#define __USER_LIBS_ULIB_H__
+
+#include <defs.h>
+
+void __warn(const char *file, int line, const char *fmt, ...);
+void __noreturn __panic(const char *file, int line, const char *fmt, ...);
+
+#define warn(...)                                       \
+    __warn(__FILE__, __LINE__, __VA_ARGS__)
+
+#define panic(...)                                      \
+    __panic(__FILE__, __LINE__, __VA_ARGS__)
+
+#define assert(x)                                       \
+    do {                                                \
+        if (!(x)) {                                     \
+            panic("assertion failed: %s", #x);          \
+        }                                               \
+    } while (0)
+
+// static_assert(x) will generate a compile-time error if 'x' is false.
+#define static_assert(x)                                \
+    switch (x) { case 0: case (x): ; }
+
+void __noreturn exit(int error_code);
+int fork(void);
+int wait(void);
+int waitpid(int pid, int *store);
+void yield(void);
+int kill(int pid);
+int getpid(void);
+void print_pgdir(void);
+
+#endif /* !__USER_LIBS_ULIB_H__ */
+

related_info/lab5/lab5-spoc-discuss/user/libs/umain.c

@@ -0,0 +1,10 @@
+#include <ulib.h>
+
+int main(void);
+
+void
+umain(void) {
+    int ret = main();
+    exit(ret);
+}
+