target/riscv/cpu_user.h

   1 #define xRA 1   /* return address (aka link register) */
   2 #define xSP 2   /* stack pointer */
   3 #define xGP 3   /* global pointer */
   4 #define xTP 4   /* thread pointer */
   5
   6 #define xA0 10  /* gpr[10-17] are syscall arguments */
   7 #define xA1 11
   8 #define xA2 12
   9 #define xA3 13
  10 #define xA4 14
  11 #define xA5 15
  12 #define xA6 16
  13 #define xA7 17  /* syscall number goes here */