Clarify mcause 0 message

Author: object-Object

src/debugger.mlog.jinja

@@ -755,18 +755,18 @@ format_uart__rx_fifo_size__no_overrun:
     set @counter ret
 
 format_mcause:
-    jump format_null strictEqual n null
+    jump format_mcause__reset strictEqual n null
     jump format_mcause__interrupt greaterThanEq n 0x80000000
     jump format_hex greaterThan n 19
     op mul jump n 2
     op add @counter @counter jump
-    format "instr addr align"; set @counter ret
+    format "instr misalign"; set @counter ret
     format "instr access fault"; set @counter ret
     format "illegal instr"; set @counter ret
     format "breakpoint"; set @counter ret
-    format "load addr align"; set @counter ret
+    format "load misalign"; set @counter ret
     format "load access fault"; set @counter ret
-    format "store/AMO addr align"; set @counter ret
+    format "store/AMO misalign"; set @counter ret
     format "store/AMO access fault"; set @counter ret
     format "ecall from U-mode"; set @counter ret
     format "ecall from S-mode"; set @counter ret
@@ -781,6 +781,10 @@ format_mcause:
     format "software check"; set @counter ret
     format "hardware check"; set @counter ret
 
+format_mcause__reset:
+    format "reset"
+    set @counter ret
+
 format_mcause__interrupt:
     op and n2 n 0x7fffffff
     op mod rem n2 2

src/main.mlog.jinja

@@ -59,7 +59,8 @@ reset:
     set icache_var null
 
     # set mcause to 0, since we don't distinguish different reset conditions
-    write 0 {{CSRS}} "{{ 'mcause'|csr }}"
+    # use null so the debugger can tell if it's a reset or a misaligned instruction
+    write null {{CSRS}} "{{ 'mcause'|csr }}"
 
     # clear LR/SC reservation set
     set reservation_set null