// See LICENSE for license details.

#include "encoding.h"
#include "bits.h"

  .macro save_tf
  # save gprs
  STORE  x1,1*REGBYTES(x2)
  STORE  x3,3*REGBYTES(x2)
  STORE  x4,4*REGBYTES(x2)
  STORE  x5,5*REGBYTES(x2)
  STORE  x6,6*REGBYTES(x2)
  STORE  x7,7*REGBYTES(x2)
  STORE  x8,8*REGBYTES(x2)
  STORE  x9,9*REGBYTES(x2)
  STORE  x10,10*REGBYTES(x2)
  STORE  x11,11*REGBYTES(x2)
  STORE  x12,12*REGBYTES(x2)
  STORE  x13,13*REGBYTES(x2)
  STORE  x14,14*REGBYTES(x2)
  STORE  x15,15*REGBYTES(x2)
  STORE  x16,16*REGBYTES(x2)
  STORE  x17,17*REGBYTES(x2)
  STORE  x18,18*REGBYTES(x2)
  STORE  x19,19*REGBYTES(x2)
  STORE  x20,20*REGBYTES(x2)
  STORE  x21,21*REGBYTES(x2)
  STORE  x22,22*REGBYTES(x2)
  STORE  x23,23*REGBYTES(x2)
  STORE  x24,24*REGBYTES(x2)
  STORE  x25,25*REGBYTES(x2)
  STORE  x26,26*REGBYTES(x2)
  STORE  x27,27*REGBYTES(x2)
  STORE  x28,28*REGBYTES(x2)
  STORE  x29,29*REGBYTES(x2)
  STORE  x30,30*REGBYTES(x2)
  STORE  x31,31*REGBYTES(x2)

  # get sr, epc, badvaddr, cause
  addi   t0,sp,320
  csrrw  t0,sscratch,t0
  csrr   t1,sstatus
  csrr   t2,sepc
  csrr   t3,scause
  STORE  t0,2*REGBYTES(x2)
  STORE  t1,32*REGBYTES(x2)
  STORE  t2,33*REGBYTES(x2)
  STORE  t3,35*REGBYTES(x2)

  # get faulting insn, if it wasn't a fetch-related trap
  li x5,-1
  STORE x5,36*REGBYTES(x2)
1:
  .endm

  .text
  .global  trap_entry
trap_entry:
  csrrw sp, sscratch, sp

1:addi sp,sp,-320
  save_tf
  move  a0,sp
  j   handle_trap
  
  .globl  pop_tf
pop_tf:  # write the trap frame onto the stack
  # restore sstatus and epc
  csrc sstatus, SSTATUS_IE
  li t0, SSTATUS_PS
  LOAD t1, 32*REGBYTES(a0)
  LOAD t2, 33*REGBYTES(a0)
  csrc sstatus, t0
  and t0, t0, t1
  csrs sstatus, t0
  csrw sepc, t2

  # restore x registers
  LOAD  x1,1*REGBYTES(a0)
  LOAD  x2,2*REGBYTES(a0)
  LOAD  x3,3*REGBYTES(a0)
  LOAD  x4,4*REGBYTES(a0)
  LOAD  x5,5*REGBYTES(a0)
  LOAD  x6,6*REGBYTES(a0)
  LOAD  x7,7*REGBYTES(a0)
  LOAD  x8,8*REGBYTES(a0)
  LOAD  x9,9*REGBYTES(a0)
  LOAD  x11,11*REGBYTES(a0)
  LOAD  x12,12*REGBYTES(a0)
  LOAD  x13,13*REGBYTES(a0)
  LOAD  x14,14*REGBYTES(a0)
  LOAD  x15,15*REGBYTES(a0)
  LOAD  x16,16*REGBYTES(a0)
  LOAD  x17,17*REGBYTES(a0)
  LOAD  x18,18*REGBYTES(a0)
  LOAD  x19,19*REGBYTES(a0)
  LOAD  x20,20*REGBYTES(a0)
  LOAD  x21,21*REGBYTES(a0)
  LOAD  x22,22*REGBYTES(a0)
  LOAD  x23,23*REGBYTES(a0)
  LOAD  x24,24*REGBYTES(a0)
  LOAD  x25,25*REGBYTES(a0)
  LOAD  x26,26*REGBYTES(a0)
  LOAD  x27,27*REGBYTES(a0)
  LOAD  x28,28*REGBYTES(a0)
  LOAD  x29,29*REGBYTES(a0)
  LOAD  x30,30*REGBYTES(a0)
  LOAD  x31,31*REGBYTES(a0)
  # restore a0 last
  LOAD  x10,10*REGBYTES(a0)

  # gtfo
  sret