bc: simplify representation of 0.5 in sqrt()

function                                             old     new   delta
zxc_program_exec                                    4012    4149    +137
zdc_program_printStream                              144       -    -144
------------------------------------------------------------------------------
(add/remove: 0/1 grow/shrink: 1/0 up/down: 137/-144)           Total: -7 bytes

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

diff --git a/miscutils/bc.c b/miscutils/bc.c
index 500d97123f58fa7d123a4ff4605c14995c831426..081e48ba87cab0d9eb6392eecf884c92753f7abb 100644 (file)
--- a/miscutils/bc.c
+++ b/miscutils/bc.c
@@ -2157,6 +2157,7 @@ static BC_STATUS zbc_num_sqrt(BcNum *a, BcNum *restrict b, size_t scale)
 {
        BcStatus s;
        BcNum num1, num2, half, f, fprime, *x0, *x1, *temp;
+       BcDig half_digs[1];
        size_t pow, len, digs, digs1, resrdx, req, times = 0;
        ssize_t cmp = 1, cmp1 = SSIZE_MAX, cmp2 = SSIZE_MAX;
 
@@ -2181,10 +2182,11 @@ static BC_STATUS zbc_num_sqrt(BcNum *a, BcNum *restrict b, size_t scale)
 
        bc_num_init(&num1, len);
        bc_num_init(&num2, len);
-       bc_num_init_DEF_SIZE(&half);
 
+       half.cap = ARRAY_SIZE(half_digs);
+       half.num = half_digs;
        bc_num_one(&half);
-       half.num[0] = 5;
+       half_digs[0] = 5;
        half.rdx = 1;
 
        bc_num_init(&f, len);
@@ -2247,7 +2249,6 @@ static BC_STATUS zbc_num_sqrt(BcNum *a, BcNum *restrict b, size_t scale)
  err:
        bc_num_free(&fprime);
        bc_num_free(&f);
-       bc_num_free(&half);
        bc_num_free(&num2);
        bc_num_free(&num1);
        RETURN_STATUS(s);
@@ -2285,7 +2286,7 @@ static BC_STATUS zdc_num_modexp(BcNum *a, BcNum *b, BcNum *c, BcNum *restrict d)
 {
        BcStatus s;
        BcNum base, exp, two, temp;
-       BcDig two_digs[2];
+       BcDig two_digs[1];
 
        if (c->len == 0)
                RETURN_STATUS(bc_error("divide by zero"));
@@ -5125,15 +5126,19 @@ static BC_STATUS zxc_program_num(BcResult *r, BcNum **num)
        case XC_RESULT_ARRAY:
        case XC_RESULT_ARRAY_ELEM: {
                BcVec *v;
-
+               void *p;
                v = xc_program_search(r->d.id.name, r->t == XC_RESULT_VAR);
-
+// dc variables are all stacks, so here we have this:
+               p = bc_vec_top(v);
+// TODO: eliminate these stacks for bc-only config?
                if (r->t == XC_RESULT_ARRAY_ELEM) {
-                       v = bc_vec_top(v);
-                       if (v->len <= r->d.id.idx) bc_array_expand(v, r->d.id.idx + 1);
+                       v = p;
+                       if (v->len <= r->d.id.idx)
+                               bc_array_expand(v, r->d.id.idx + 1);
                        *num = bc_vec_item(v, r->d.id.idx);
-               } else
-                       *num = bc_vec_top(v);
+               } else {
+                       *num = p;
+               }
                break;
        }
 #if ENABLE_BC