ma_fetch.S

# See LICENSE for license details.

#*****************************************************************************
# ma_fetch.S
#-----------------------------------------------------------------------------
#
# Test misaligned fetch trap.
#

#include "riscv_test.h"
#include "test_macros.h"

RVTEST_RV64S
RVTEST_CODE_BEGIN

#ifdef __MACHINE_MODE
  #define sscratch mscratch
  #define sstatus mstatus
  #define scause mcause
  #define stval mtval
  #define sepc mepc
  #define sret mret
  #define stvec_handler mtvec_handler
#endif

  .align 2
  .option norvc

  # Without RVC, the jalr should trap, and the handler will skip ahead.
  # With RVC, the jalr should not trap, and "j fail" should get skipped.
  li TESTNUM, 2
  li t1, 0
  la t0, 1f
  jalr t1, t0, 2
1:
  .option rvc
  c.j 1f
  c.j 2f
  .option norvc
1:
  j fail
2:

  // This test should pass, since JALR ignores the target LSB
  li TESTNUM, 3
  la t0, 1f
  jalr t1, t0, 1
1:
  j 1f
  j fail
1:

  li TESTNUM, 4
  li t1, 0
  la t0, 1f
  jalr t1, t0, 3
1:
  .option rvc
  c.j 1f
  c.j 2f
  .option norvc
1:
  j fail
2:

  # Like test 2, but with jal instead of jalr.
  li TESTNUM, 5
  li t1, 0
  la t0, 1f
  jal t1, 2f
1:
  .option rvc
  c.j 1f
2:
  c.j 2f
  .option norvc
1:
  j fail
2:

  # Like test 2, but with a taken branch instead of jalr.
  li TESTNUM, 6
  li t1, 0
  la t0, 1f
  beqz x0, 2f
1:
  .option rvc
  c.j 1f
2:
  c.j 2f
  .option norvc
1:
  j fail
2:

  # Not-taken branches should not trap, even without RVC.
  li TESTNUM, 7
  bnez x0, 1f
  j 2f
  .option rvc
  c.j 1f
1:
  c.j 1f
  .option norvc
1:
  j fail
2:

#ifdef __MACHINE_MODE
  # Skip if C cannot be enabled
  csrsi misa, 1 << ('c' - 'a')
  csrr t2, misa
  andi t2, t2, 1 << ('c' - 'a')
  beqz t2, pass

  # Skip if C cannot be disabled
  csrci misa, 1 << ('c' - 'a')
  csrr t2, misa
  andi t2, t2, 1 << ('c' - 'a')
  bnez t2, pass

  # Skip if clearing misa.C does not set IALIGN=32
  csrr t0, mtvec
  la t1, 1f
  addi t1, t1, 2
  csrw mtvec, t1
  j 1f

  .option rvc
  c.nop
1:
  j pass
  .option norvc
2:
  csrw mtvec, t0
  csrsi misa, 1 << ('c' - 'a')

  # IALIGN=32 cannot be set if doing so would cause a misaligned instruction
  # exception on the next instruction fetch. (This test assumes no other
  # extensions that support misalignment are present.)
  li TESTNUM, 8
  csrr t2, misa
  andi t2, t2, 1 << ('c' - 'a')
  beqz t2, pass

  .option rvc
  c.nop
  csrci misa, 1 << ('c' - 'a')
1:
  c.nop
  .option norvc

  csrr t2, misa
  andi t2, t2, 1 << ('c' - 'a')
  beqz t2, fail

  # IALIGN=32, mret to a misaligned mepc should succeed,
  # masking off mepc[1].
  la t0, 1f
  addi t0, t0, -2
  csrw mepc, t0

  csrci misa, 1 << ('c' - 'a')
  li t2, MSTATUS_MPP
  csrs mstatus, t2
  mret

  # mret should transfer control to this branch.  Otherwise, it will
  # transfer control two bytes into the branch, which happens to be the
  # illegal instruction c.unimp.
  beqz x0, 1f
1:
  csrsi misa, 1 << ('c' - 'a')
#endif

  j pass

  TEST_PASSFAIL

  .align 2
  .global stvec_handler
stvec_handler:
  # tests 2, 4, 5, 6, and 8 should trap
  li a0, 2
  beq TESTNUM, a0, 1f
  li a0, 4
  beq TESTNUM, a0, 1f
  li a0, 5
  beq TESTNUM, a0, 1f
  li a0, 6
  beq TESTNUM, a0, 1f
  j fail
1:

  # verify that return address was not written
  bnez t1, fail

  # verify trap cause
  li a1, CAUSE_MISALIGNED_FETCH
  csrr a0, scause
  bne a0, a1, fail

  # verify that epc == &jalr (== t0 - 4)
  csrr a1, sepc
  addi a1, a1, 4
  bne t0, a1, fail

  # verify that tval == 0 or tval == t0+2.
  csrr a0, stval
  beqz a0, 1f
  addi a0, a0, -2
  bne a0, t0, fail
1:

  addi a1, a1, 8
  csrw sepc, a1
  sret

RVTEST_CODE_END

  .data
RVTEST_DATA_BEGIN

  TEST_DATA

RVTEST_DATA_END