src/thread/riscv32/clone.s

   1 # __clone(func, stack, flags, arg, ptid, tls, ctid)
   2 #           a0,    a1,    a2,  a3,   a4,  a5,   a6
   3
   4 # syscall(SYS_clone, flags, stack, ptid, tls, ctid)
   5 #                a7     a0,    a1,   a2,  a3,   a4
   6
   7 .global __clone
   8 .type  __clone, %function
   9 __clone:
  10         # Save func and arg to stack
  11         addi a1, a1, -16
  12         sw a0, 0(a1)
  13         sw a3, 4(a1)
  14
  15         # Call SYS_clone
  16         mv a0, a2
  17         mv a2, a4
  18         mv a3, a5
  19         mv a4, a6
  20         li a7, 220 # SYS_clone
  21         ecall
  22
  23         beqz a0, 1f
  24         # Parent
  25         ret
  26
  27         # Child
  28 1:      lw a1, 0(sp)
  29         lw a0, 4(sp)
  30         jalr a1
  31
  32         # Exit
  33         li a7, 93 # SYS_exit
  34         ecall