#include <assert.h>
#include <unistd.h>
#include <signal.h>
#define CRF_LT (1 << 3)
#define CRF_GT (1 << 2)
#define CRF_EQ (1 << 1)
#define CRF_SO (1 << 0)
#define UNDEF 0
#define BCDSUB(vra, vrb, ps) \
asm ("bcdsub. %1,%2,%3,%4;" \
"mfocrf %0,0b10;" \
: "=r" (cr), "=v" (vrt) \
: "v" (vra), "v" (vrb), "i" (ps) \
: );
#define TEST(vra, vrb, ps, exp_res, exp_cr6) \
do { \
__int128 vrt = 0; \
int cr = 0; \
BCDSUB(vra, vrb, ps); \
if (exp_res) \
assert(vrt == exp_res); \
assert((cr >> 4) == exp_cr6); \
} while (0)
/*
* Unbounded result is equal to zero:
* sign = (PS) ? 0b1111 : 0b1100
* CR6 = 0b0010
*/
void test_bcdsub_eq(void)
{
__int128 a, b;
/* maximum positive BCD value */
a = b = (((__int128) 0x9999999999999999) << 64 | 0x999999999999999c);
TEST(a, b, 0, 0xc, CRF_EQ);
TEST(a, b, 1, 0xf, CRF_EQ);
}
/*
* Unbounded result is greater than zero:
* sign = (PS) ? 0b1111 : 0b1100
* CR6 = (overflow) ? 0b0101 : 0b0100
*/
void test_bcdsub_gt(void)
{
__int128 a, b, c;
/* maximum positive BCD value */
a = (((__int128) 0x9999999999999999) << 64 | 0x999999999999999c);
/* negative one BCD value */
b = (__int128) 0x1d;
TEST(a, b, 0, 0xc, (CRF_GT | CRF_SO));
TEST(a, b, 1, 0xf, (CRF_GT | CRF_SO));
c = (((__int128) 0x9999999999999999) << 64 | 0x999999999999998c);
TEST(c, b, 0, a, CRF_GT);
TEST(c, b, 1, (a | 0x3), CRF_GT);
}
/*
* Unbounded result is less than zero:
* sign = 0b1101
* CR6 = (overflow) ? 0b1001 : 0b1000
*/
void test_bcdsub_lt(void)
{
__int128 a, b;
/* positive zero BCD value */
a = (__int128) 0xc;
/* positive one BCD value */
b = (__int128) 0x1c;
TEST(a, b, 0, 0x1d, CRF_LT);
TEST(a, b, 1, 0x1d, CRF_LT);
/* maximum negative BCD value */
a = (((__int128) 0x9999999999999999) << 64 | 0x999999999999999d);
/* positive one BCD value */
b = (__int128) 0x1c;
TEST(a, b, 0, 0xd, (CRF_LT | CRF_SO));
TEST(a, b, 1, 0xd, (CRF_LT | CRF_SO));
}
void test_bcdsub_invalid(void)
{
__int128 a, b;
/* positive one BCD value */
a = (__int128) 0x1c;
b = 0xf00;
TEST(a, b, 0, UNDEF, CRF_SO);
TEST(a, b, 1, UNDEF, CRF_SO);
TEST(b, a, 0, UNDEF, CRF_SO);
TEST(b, a, 1, UNDEF, CRF_SO);
a = 0xbad;
TEST(a, b, 0, UNDEF, CRF_SO);
TEST(a, b, 1, UNDEF, CRF_SO);
}
int main(void)
{
struct sigaction action;
action.sa_handler = _exit;
sigaction(SIGABRT, &action, NULL);
test_bcdsub_eq();
test_bcdsub_gt();
test_bcdsub_lt();
test_bcdsub_invalid();
return 0;
}
