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88 lines
1.9 KiB
88 lines
1.9 KiB
6 years ago
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#ifdef RISCV_QEMU
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# define SYS_write 64
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# define SYS_exit 93
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long syscall(long a0, long a1, long a2, long a3, long a4, long a5, long a6) {
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register long _0 __asm__("a7") = a0;
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register long _1 __asm__("a0") = a1;
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register long _2 __asm__("a1") = a2;
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register long _3 __asm__("a2") = a3;
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register long _4 __asm__("a3") = a4;
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register long _5 __asm__("a4") = a5;
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register long _6 __asm__("a5") = a6;
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__asm__ __volatile__("ecall":::);
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return _1;
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}
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#else
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# define SYS_write 103
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# define SYS_exit 1
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# define SYS_fork 2
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# define SYS_putc 30
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# define SYS_getpid 18
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# define SYS_sleep 11
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long syscall(long a0, long a1, long a2, long a3, long a4, long a5, long a6) {
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register long _0 __asm__("x10") = a0;
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register long _1 __asm__("x11") = a1;
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register long _2 __asm__("x12") = a2;
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register long _3 __asm__("x13") = a3;
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register long _4 __asm__("x14") = a4;
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register long _5 __asm__("x15") = a5;
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register long _6 __asm__("x16") = a6;
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__asm__ __volatile__("ecall":::);
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return _0;
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}
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#endif
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const char* welcome_msg = "hello world!\n";
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const char* hexch = "0123456789ABCDEF";
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void putc(char c) {
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syscall(SYS_putc, c, 0, 0, 0, 0, 0);
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}
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void putstr(const char* s) {
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for (; *s; s++)
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syscall(SYS_putc, *s, 0, 0, 0, 0, 0);
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}
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void putint_hex(long v) {
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char ch[18];
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ch[16] = 'H';
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ch[17] = 0;
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for (int i = 15; i >= 0; i--) {
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ch[i] = hexch[v & 15];
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v >>= 4;
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}
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putstr(ch);
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}
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void _start() {
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putstr(welcome_msg);
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putc('\n');
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putstr("my pid is ");
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long v = syscall(SYS_getpid, 0, 0, 0, 0, 0, 0);
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putint_hex(v);
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putc('\n');
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long v1 = syscall(SYS_fork, 0, 0, 0, 0, 0, 0);
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putstr("fork returned: ");
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putint_hex(v1);
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putc('\n');
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if (v1 != 0) {
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putstr("parent sleeping");
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putc('\n');
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syscall(SYS_sleep, 200, 0, 0, 0, 0, 0);
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}
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putstr("my pid is ");
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v = syscall(SYS_getpid, 0, 0, 0, 0, 0, 0);
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putint_hex(v);
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putc('\n');
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putint_hex(v);
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putstr(" is exiting");
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putc('\n');
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syscall(SYS_exit, 0, 0, 0, 0, 0, 0);
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}
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