From 652ec8c0c98bfc64bbc8d036d89c61066aebee91 Mon Sep 17 00:00:00 2001 From: Andrew Waterman Date: Thu, 9 Nov 2017 17:12:49 -0800 Subject: [PATCH] Use mstatus.MPP to check existence of U-mode misa is allowed to be hardwired to 0, so checking its U bit could incorrectly suggest that U-mode is not supported. --- isa/rv64si/csr.S | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/isa/rv64si/csr.S b/isa/rv64si/csr.S index 5a8edbe..dbe1c05 100644 --- a/isa/rv64si/csr.S +++ b/isa/rv64si/csr.S @@ -26,13 +26,14 @@ RVTEST_CODE_BEGIN # For RV64, make sure UXL encodes RV64. (UXL does not exist for RV32.) #if __riscv_xlen == 64 - # If running in M mode, read misa to check existence of U mode. + # If running in M mode, use mstatus.MPP to check existence of U mode. # Otherwise, if in S mode, then U mode must exist and we don't need to check. #ifdef __MACHINE_MODE - csrr a0, misa - srli a0, a0, 'U' - 'A' - andi a0, a0, 1 - beqz a0, 1f + li t0, MSTATUS_MPP + csrc mstatus, t0 + csrr t1, mstatus + and t0, t0, t1 + bnez t0, 1f #endif # If U mode is present, UXL should be 2 (XLEN = 64-bit) TEST_CASE(13, a0, SSTATUS_UXL & (SSTATUS_UXL << 1), csrr a0, sstatus; li a1, SSTATUS_UXL; and a0, a0, a1) -- 2.30.2