diff options
| -rw-r--r-- | riscv/riscv.sail | 18 |
1 files changed, 14 insertions, 4 deletions
diff --git a/riscv/riscv.sail b/riscv/riscv.sail index 0c3fa944..d93c7dae 100644 --- a/riscv/riscv.sail +++ b/riscv/riscv.sail @@ -540,8 +540,12 @@ union clause ast = MRET : unit function clause decode 0b0011000 @ 0b00010 @ 0b00000 @ 0b000 @ 0b00000 @ 0b1110011 = Some(MRET()) -function clause execute MRET() = - nextPC = handle_exception(cur_privilege, CTL_MRET(), PC) +function clause execute MRET() = { + if cur_privilege == Machine then + nextPC = handle_exception(cur_privilege, CTL_MRET(), PC) + else + handle_illegal() +} function clause print_insn (MRET()) = "mret" @@ -549,10 +553,16 @@ function clause print_insn (MRET()) = /* ****************************************************************** */ union clause ast = SRET : unit -function clause decode 0b0001000 @ 0b00010 @ 0b00000 @ 0b000 @ 0b00000 @ 0b1110011 = Some(MRET()) +function clause decode 0b0001000 @ 0b00010 @ 0b00000 @ 0b000 @ 0b00000 @ 0b1110011 = Some(SRET()) function clause execute SRET() = - nextPC = handle_exception(cur_privilege, CTL_SRET(), PC) + match cur_privilege { + User => handle_illegal(), + Supervisor => if mstatus.TSR() == true + then handle_illegal() + else nextPC = handle_exception(cur_privilege, CTL_SRET(), PC), + Machine => nextPC = handle_exception(cur_privilege, CTL_SRET(), PC) + } function clause print_insn (SRET()) = "sret" |