shell/math: code shrink

function                                             old     new   delta
arith_apply                                         1015    1023      +8
evaluate_string                                     1309    1295     -14
.rodata                                           105344  105321     -23
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/2 up/down: 8/-37)             Total: -29 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 10 insertions, 8 deletions

diff --git a/shell/math.c b/shell/math.c
index 9e81d604c..e15b014aa 100644
--- a/shell/math.c
+++ b/shell/math.c
@@ -141,6 +141,7 @@ typedef unsigned char operator;
  * but there are 11 of them, which doesn't fit into 3 bits for unique id.
  * Abusing another precedence level:
  */
+#define PREC_ASSIGN1            2
 #define TOK_ASSIGN              tok_decl(2,0)
 #define TOK_AND_ASSIGN          tok_decl(2,1)
 #define TOK_OR_ASSIGN           tok_decl(2,2)
@@ -150,11 +151,12 @@ typedef unsigned char operator;
 #define TOK_LSHIFT_ASSIGN       tok_decl(2,6)
 #define TOK_RSHIFT_ASSIGN       tok_decl(2,7)
 
+#define PREC_ASSIGN2            3
 #define TOK_MUL_ASSIGN          tok_decl(3,0)
 #define TOK_DIV_ASSIGN          tok_decl(3,1)
 #define TOK_REM_ASSIGN          tok_decl(3,2)
 
-#define fix_assignment_prec(prec) do { if (prec == 3) prec = 2; } while (0)
+#define fix_assignment_prec(prec) do { prec -= (prec == 3); } while (0)
 
 /* Ternary conditional operator is right associative too */
 /*
@@ -211,25 +213,25 @@ typedef unsigned char operator;
 #define TOK_UPLUS               tok_decl(UNARYPREC+1,1)
 
 #define PREC_PRE                (UNARYPREC+2)
-#define TOK_PRE_INC             tok_decl(PREC_PRE, 0)
-#define TOK_PRE_DEC             tok_decl(PREC_PRE, 1)
+#define TOK_PRE_INC             tok_decl(PREC_PRE,0)
+#define TOK_PRE_DEC             tok_decl(PREC_PRE,1)
 
 #define PREC_POST               (UNARYPREC+3)
-#define TOK_POST_INC            tok_decl(PREC_POST, 0)
-#define TOK_POST_DEC            tok_decl(PREC_POST, 1)
+#define TOK_POST_INC            tok_decl(PREC_POST,0)
+#define TOK_POST_DEC            tok_decl(PREC_POST,1)
 
 /* TOK_VALUE marks a number, name, name++/name--, or (EXPR):
  * IOW: something which can be used as the left side of a binary op.
  * Since it's never pushed to opstack, its precedence does not matter.
  */
-#define TOK_VALUE               tok_decl(PREC_POST, 2)
+#define TOK_VALUE               tok_decl(PREC_POST,2)
 
 static int
 is_assign_op(operator op)
 {
         operator prec = PREC(op);
-        fix_assignment_prec(prec);
-        return prec == PREC(TOK_ASSIGN)
+        return prec == PREC_ASSIGN1
+        || prec == PREC_ASSIGN2
         || prec == PREC_PRE
         || prec == PREC_POST;
 }