dc: code shrink

function                                             old     new   delta
check_under                                           20      21      +1
print_no_pop                                          32      27      -5
pop                                                   24      18      -6
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/2 up/down: 1/-11)             Total: -10 bytes

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

1 files changed, 16 insertions, 6 deletions

diff --git a/miscutils/dc.c b/miscutils/dc.c
index 17fdda8fd..5119c1383 100644
--- a/miscutils/dc.c
+++ b/miscutils/dc.c
@@ -35,10 +35,12 @@ enum { STACK_SIZE = (COMMON_BUFSIZE - offsetof(struct globals, stack)) / sizeof(
         base = 10; \
 } while (0)
 
-static void check_under(void)
+static unsigned check_under(void)
 {
-        if (pointer == 0)
+        unsigned p = pointer;
+        if (p == 0)
                 bb_error_msg_and_die("stack underflow");
+        return p - 1;
 }
 
 static void push(double a)
@@ -50,8 +52,9 @@ static void push(double a)
 
 static double pop(void)
 {
-        check_under();
-        return stack[--pointer];
+        unsigned p = check_under();
+        pointer = p;
+        return stack[p];
 }
 
 static void add(void)
@@ -91,6 +94,14 @@ static void mod(void)
 {
         data_t d = pop();
 
+        //if (d == 0) {
+        //      bb_error_msg("remainder by zero");
+        //      pop();
+        //      push(0);
+        //      return;
+        //}
+        //^^^^ without this, we simply get SIGFPE and die
+
         push((data_t) pop() % d);
 }
 
@@ -171,8 +182,7 @@ static void print_stack_no_pop(void)
 
 static void print_no_pop(void)
 {
-        check_under();
-        print_base(stack[pointer-1]);
+        print_base(stack[check_under()]);
 }
 
 struct op {