#include <stdint.h>
#include <string.h>
#include <stdarg.h>
+#include <stdio.h>
+#include <limits.h>
#include <machine/syscall.h>
#include "encoding.h"
-void exit(int code)
+#define SYS_stats 1234
+#define static_assert(cond) switch(0) { case 0: case !!(long)(cond): ; }
+
+static long handle_frontend_syscall(long which, long arg0, long arg1, long arg2)
{
- volatile uint64_t magic_mem[8] = {0};
- magic_mem[0] = SYS_exit;
- magic_mem[1] = code;
+ volatile uint64_t magic_mem[8] __attribute__((aligned(64)));
+ magic_mem[0] = which;
+ magic_mem[1] = arg0;
+ magic_mem[2] = arg1;
+ magic_mem[3] = arg2;
__sync_synchronize();
write_csr(tohost, (long)magic_mem);
- while(1);
+ while (swap_csr(fromhost, 0) == 0);
+ return magic_mem[0];
+}
+
+// In setStats, we might trap reading uarch-specific counters.
+// The trap handler will skip over the instruction and write 0,
+// but only if v0 is the destination register.
+#define read_csr_safe(reg) ({ register long __tmp asm("v0"); \
+ asm volatile ("csrr %0, " #reg : "=r"(__tmp)); \
+ __tmp; })
+
+#define NUM_COUNTERS 18
+static long counters[NUM_COUNTERS];
+static char* counter_names[NUM_COUNTERS];
+static int handle_stats(int enable)
+{
+ int i = 0;
+#define READ_CTR(name) do { \
+ while (i >= NUM_COUNTERS) ; \
+ long csr = read_csr_safe(name); \
+ if (!enable) { csr -= counters[i]; counter_names[i] = #name; } \
+ counters[i++] = csr; \
+ } while (0)
+ READ_CTR(cycle); READ_CTR(instret);
+ READ_CTR(uarch0); READ_CTR(uarch1); READ_CTR(uarch2); READ_CTR(uarch3);
+ READ_CTR(uarch4); READ_CTR(uarch5); READ_CTR(uarch6); READ_CTR(uarch7);
+ READ_CTR(uarch8); READ_CTR(uarch9); READ_CTR(uarch10); READ_CTR(uarch11);
+ READ_CTR(uarch12); READ_CTR(uarch13); READ_CTR(uarch14); READ_CTR(uarch15);
+#undef READ_CTR
+ return 0;
+}
+
+static void tohost_exit(int code)
+{
+ write_csr(tohost, (code << 1) | 1);
+ while (1);
+}
+
+long handle_trap(long cause, long epc, long regs[32])
+{
+ int csr_insn;
+ asm volatile ("lw %0, 1f; j 2f; 1: csrr v0, uarch0; 2:" : "=r"(csr_insn));
+ long sys_ret = 0;
+
+ if (cause == CAUSE_ILLEGAL_INSTRUCTION &&
+ (*(int*)epc & csr_insn) == csr_insn)
+ ;
+ else if (cause != CAUSE_SYSCALL)
+ tohost_exit(1337);
+ else if (regs[16] == SYS_exit)
+ tohost_exit(regs[18]);
+ else if (regs[16] == SYS_stats)
+ sys_ret = handle_stats(regs[18]);
+ else
+ sys_ret = handle_frontend_syscall(regs[16], regs[18], regs[19], regs[20]);
+
+ regs[16] = sys_ret;
+ return epc+4;
+}
+
+static long syscall(long num, long arg0, long arg1, long arg2)
+{
+ register long v0 asm("v0") = num;
+ register long a0 asm("a0") = arg0;
+ register long a1 asm("a1") = arg1;
+ register long a2 asm("a2") = arg2;
+ asm volatile ("scall" : "+r"(v0) : "r"(a0), "r"(a1), "r"(a2) : "s0");
+ return v0;
+}
+
+void exit(int code)
+{
+ syscall(SYS_exit, code, 0, 0);
+}
+
+void setStats(int enable)
+{
+ syscall(SYS_stats, enable, 0, 0);
}
void printstr(const char* s)
{
- volatile uint64_t magic_mem[8] = {0};
- magic_mem[0] = SYS_write;
- magic_mem[1] = 1;
- magic_mem[2] = (unsigned long)s;
- magic_mem[3] = strlen(s);
- __sync_synchronize();
- write_csr(tohost, (long)magic_mem);
- while (swap_csr(fromhost, 0) == 0);
+ syscall(SYS_write, 1, (long)s, strlen(s));
+}
+
+void __attribute__((weak)) thread_entry(int cid, int nc)
+{
+ // multi-threaded programs override this function.
+ // for the case of single-threaded programs, only let core 0 proceed.
+ while (cid != 0);
}
+int __attribute__((weak)) main(int argc, char** argv)
+{
+ // single-threaded programs override this function.
+ printstr("Implement main(), foo!\n");
+ return -1;
+}
+
+void _init(int cid, int nc)
+{
+ thread_entry(cid, nc);
+
+ // only single-threaded programs should ever get here.
+ int ret = main(0, 0);
+
+ char buf[NUM_COUNTERS * 32] __attribute__((aligned(64)));
+ char* pbuf = buf;
+ for (int i = 0; i < NUM_COUNTERS; i++)
+ if (counters[i])
+ pbuf += sprintf(pbuf, "%s = %d\n", counter_names[i], counters[i]);
+ if (pbuf != buf)
+ printstr(buf);
+
+ exit(ret);
+}
+
+#undef putchar
int putchar(int ch)
{
- static char buf[64];
+ static char buf[64] __attribute__((aligned(64)));
static int buflen = 0;
- if(ch != -1)
- buf[buflen++] = ch;
+ buf[buflen++] = ch;
- if(ch == -1 || buflen == sizeof(buf))
+ if (ch == '\n' || buflen == sizeof(buf))
{
- volatile uint64_t magic_mem[8] = {0};
- magic_mem[0] = SYS_write;
- magic_mem[1] = 1;
- magic_mem[2] = (long)buf;
- magic_mem[3] = buflen;
- __sync_synchronize();
- write_csr(tohost, (long)magic_mem);
- while (swap_csr(fromhost, 0) == 0);
-
+ syscall(SYS_write, 1, (long)buf, buflen);
buflen = 0;
}
printstr(str);
}
-static void printnum(void (*putch)(int, void**), void **putdat,
- unsigned long long num, unsigned base, int width, int padc)
+static inline void printnum(void (*putch)(int, void**), void **putdat,
+ unsigned long long num, unsigned base, int width, int padc)
{
- if (num >= base)
- printnum(putch, putdat, num / base, base, width - 1, padc);
- else while (--width > 0)
+ unsigned digs[sizeof(num)*CHAR_BIT];
+ int pos = 0;
+
+ while (1)
+ {
+ digs[pos++] = num % base;
+ if (num < base)
+ break;
+ num /= base;
+ }
+
+ while (width-- > pos)
putch(padc, putdat);
- putch("0123456789abcdef"[num % base], putdat);
+ while (pos-- > 0)
+ putch(digs[pos] + (digs[pos] >= 10 ? 'a' - 10 : '0'), putdat);
}
static unsigned long long getuint(va_list *ap, int lflag)
return va_arg(*ap, int);
}
-void vprintfmt(void (*putch)(int, void**), void **putdat, const char *fmt, va_list ap)
+static void vprintfmt(void (*putch)(int, void**), void **putdat, const char *fmt, va_list ap)
{
register const char* p;
const char* last_fmt;
for (width -= strnlen(p, precision); width > 0; width--)
putch(padc, putdat);
for (; (ch = *p) != '\0' && (precision < 0 || --precision >= 0); width--) {
- if (altflag && (ch < ' ' || ch > '~'))
- putch('?', putdat);
- else
- putch(ch, putdat);
+ putch(ch, putdat);
p++;
}
for (; width > 0; width--)
num = -(long long) num;
}
base = 10;
- goto number;
+ goto signed_number;
// unsigned decimal
case 'u':
- num = getuint(&ap, lflag);
base = 10;
- goto number;
+ goto unsigned_number;
// (unsigned) octal
case 'o':
// should do something with padding so it's always 3 octits
- num = getuint(&ap, lflag);
base = 8;
- goto number;
+ goto unsigned_number;
// pointer
case 'p':
+ static_assert(sizeof(long) == sizeof(void*));
+ lflag = 1;
putch('0', putdat);
putch('x', putdat);
- num = (unsigned long long)
- (uintptr_t) va_arg(ap, void *);
- base = 16;
- goto number;
+ /* fall through to 'x' */
// (unsigned) hexadecimal
case 'x':
- num = getuint(&ap, lflag);
base = 16;
- number:
+ unsigned_number:
+ num = getuint(&ap, lflag);
+ signed_number:
printnum(putch, putdat, num, base, width, padc);
break;
va_start(ap, fmt);
vprintfmt((void*)putchar, 0, fmt, ap);
- putchar(-1);
va_end(ap);
return 0; // incorrect return value, but who cares, anyway?
}
+
+int sprintf(char* str, const char* fmt, ...)
+{
+ va_list ap;
+ char* str0 = str;
+ va_start(ap, fmt);
+
+ void sprintf_putch(int ch, void** data)
+ {
+ char** pstr = (char**)data;
+ **pstr = ch;
+ (*pstr)++;
+ }
+
+ vprintfmt(sprintf_putch, (void**)&str, fmt, ap);
+ *str = 0;
+
+ va_end(ap);
+ return str - str0;
+}