static unsigned int BN_STACK_pop(BN_STACK *st)
{
    return st->indexes[--(st->depth)];
}
['static int file_modmul(STANZA *s)\n{\n    BIGNUM *a = NULL, *b = NULL, *m = NULL, *mod_mul = NULL, *ret = NULL;\n    int st = 0;\n    if (!TEST_ptr(a = getBN(s, "A"))\n            || !TEST_ptr(b = getBN(s, "B"))\n            || !TEST_ptr(m = getBN(s, "M"))\n            || !TEST_ptr(mod_mul = getBN(s, "ModMul"))\n            || !TEST_ptr(ret = BN_new()))\n        goto err;\n    if (!TEST_true(BN_mod_mul(ret, a, b, m, ctx))\n            || !equalBN("A * B (mod M)", mod_mul, ret))\n        goto err;\n    if (BN_is_odd(m)) {\n        BN_MONT_CTX *mont = BN_MONT_CTX_new();\n        BIGNUM *a_tmp = BN_new();\n        BIGNUM *b_tmp = BN_new();\n        if (mont == NULL || a_tmp == NULL || b_tmp == NULL\n                || !TEST_true(BN_MONT_CTX_set(mont, m, ctx))\n                || !TEST_true(BN_nnmod(a_tmp, a, m, ctx))\n                || !TEST_true(BN_nnmod(b_tmp, b, m, ctx))\n                || !TEST_true(BN_to_montgomery(a_tmp, a_tmp, mont, ctx))\n                || !TEST_true(BN_to_montgomery(b_tmp, b_tmp, mont, ctx))\n                || !TEST_true(BN_mod_mul_montgomery(ret, a_tmp, b_tmp,\n                                                    mont, ctx))\n                || !TEST_true(BN_from_montgomery(ret, ret, mont, ctx))\n                || !equalBN("A * B (mod M) (mont)", mod_mul, ret))\n            st = 0;\n        else\n            st = 1;\n        BN_MONT_CTX_free(mont);\n        BN_free(a_tmp);\n        BN_free(b_tmp);\n        if (st == 0)\n            goto err;\n    }\n    st = 1;\n err:\n    BN_free(a);\n    BN_free(b);\n    BN_free(m);\n    BN_free(mod_mul);\n    BN_free(ret);\n    return st;\n}', 'int BN_mod_mul(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, const BIGNUM *m,\n               BN_CTX *ctx)\n{\n    BIGNUM *t;\n    int ret = 0;\n    bn_check_top(a);\n    bn_check_top(b);\n    bn_check_top(m);\n    BN_CTX_start(ctx);\n    if ((t = BN_CTX_get(ctx)) == NULL)\n        goto err;\n    if (a == b) {\n        if (!BN_sqr(t, a, ctx))\n            goto err;\n    } else {\n        if (!BN_mul(t, a, b, ctx))\n            goto err;\n    }\n    if (!BN_nnmod(r, t, m, ctx))\n        goto err;\n    bn_check_top(r);\n    ret = 1;\n err:\n    BN_CTX_end(ctx);\n    return ret;\n}', 'void BN_CTX_start(BN_CTX *ctx)\n{\n    CTXDBG("ENTER BN_CTX_start()", ctx);\n    if (ctx->err_stack || ctx->too_many)\n        ctx->err_stack++;\n    else if (!BN_STACK_push(&ctx->stack, ctx->used)) {\n        BNerr(BN_F_BN_CTX_START, BN_R_TOO_MANY_TEMPORARY_VARIABLES);\n        ctx->err_stack++;\n    }\n    CTXDBG("LEAVE BN_CTX_start()", ctx);\n}', 'void BN_CTX_end(BN_CTX *ctx)\n{\n    CTXDBG("ENTER BN_CTX_end()", ctx);\n    if (ctx->err_stack)\n        ctx->err_stack--;\n    else {\n        unsigned int fp = BN_STACK_pop(&ctx->stack);\n        if (fp < ctx->used)\n            BN_POOL_release(&ctx->pool, ctx->used - fp);\n        ctx->used = fp;\n        ctx->too_many = 0;\n    }\n    CTXDBG("LEAVE BN_CTX_end()", ctx);\n}', 'static unsigned int BN_STACK_pop(BN_STACK *st)\n{\n    return st->indexes[--(st->depth)];\n}']