bt(5), btrace(8): support modulo operator ('%')

[Scott Cheloha]

This adds support for the modulo operator to btrace(8).

I was trying to use it like this:

        $start = nsecs;
        /* ... */
        $elapsed = nsecs - $start;
        printf("%d.%09d seconds\n",
            $elapsed / 1000000000, $elapsed % 1000000000);

and noticed it was missing.

ok?

Index: bt_parse.y
===================================================================
RCS file: /cvs/src/usr.sbin/btrace/bt_parse.y,v
retrieving revision 1.53
diff -u -p -r1.53 bt_parse.y
--- bt_parse.y  11 Sep 2023 19:01:26 -0000      1.53
+++ bt_parse.y  10 Oct 2023 16:07:45 -0000
@@ -184,7 +184,7 @@ filter      : /* empty */                   { $$ = NULL; }
  * Give higher precedence to:
  *  1. && and ||
  *  2. ==, !=, <<, <, >=, >, +, =, &, ^, |
- *  3. * and /
+ *  3. * , / , %
  */
 expr   : expr OP_LAND term     { $$ = ba_op(B_AT_OP_LAND, $1, $3); }
        | expr OP_LOR term      { $$ = ba_op(B_AT_OP_LOR, $1, $3); }
@@ -207,6 +207,7 @@ term        : term OP_EQ fterm      { $$ = ba_op(B_A
 
 fterm  : fterm '*' factor      { $$ = ba_op(B_AT_OP_MULT, $1, $3); }
        | fterm '/' factor      { $$ = ba_op(B_AT_OP_DIVIDE, $1, $3); }
+       | fterm '%' factor      { $$ = ba_op(B_AT_OP_MODULO, $1, $3); }
        | factor
        ;
 
Index: bt_parser.h
===================================================================
RCS file: /cvs/src/usr.sbin/btrace/bt_parser.h,v
retrieving revision 1.24
diff -u -p -r1.24 bt_parser.h
--- bt_parser.h 11 Sep 2023 19:01:26 -0000      1.24
+++ bt_parser.h 10 Oct 2023 16:07:45 -0000
@@ -163,6 +163,7 @@ struct bt_arg {
                B_AT_OP_MINUS,
                B_AT_OP_MULT,
                B_AT_OP_DIVIDE,
+               B_AT_OP_MODULO,
                B_AT_OP_BAND,
                B_AT_OP_XOR,
                B_AT_OP_BOR,
Index: btrace.c
===================================================================
RCS file: /cvs/src/usr.sbin/btrace/btrace.c,v
retrieving revision 1.78
diff -u -p -r1.78 btrace.c
--- btrace.c    15 Sep 2023 10:59:02 -0000      1.78
+++ btrace.c    10 Oct 2023 16:07:45 -0000
@@ -1416,6 +1416,9 @@ baexpr2long(struct bt_arg *ba, struct dt
        case B_AT_OP_DIVIDE:
                result = lval / rval;
                break;
+       case B_AT_OP_MODULO:
+               result = lval % rval;
+               break;
        case B_AT_OP_BAND:
                result = lval & rval;
                break;
@@ -1526,6 +1529,8 @@ ba_name(struct bt_arg *ba)
                return "*";
        case B_AT_OP_DIVIDE:
                return "/";
+       case B_AT_OP_MODULO:
+               return "%";
        case B_AT_OP_BAND:
                return "&";
        case B_AT_OP_XOR: