From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:33142) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fhwBl-0001v8-GF for qemu-devel@nongnu.org; Tue, 24 Jul 2018 08:13:14 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fhwBi-0003CA-Ps for qemu-devel@nongnu.org; Tue, 24 Jul 2018 08:13:13 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:40296 helo=mx0a-001b2d01.pphosted.com) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fhwBi-0003BK-KC for qemu-devel@nongnu.org; Tue, 24 Jul 2018 08:13:10 -0400 Received: from pps.filterd (m0098417.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w6OC9VHJ052486 for ; Tue, 24 Jul 2018 08:13:09 -0400 Received: from e16.ny.us.ibm.com (e16.ny.us.ibm.com [129.33.205.206]) by mx0a-001b2d01.pphosted.com with ESMTP id 2ke34na6kd-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Tue, 24 Jul 2018 08:13:08 -0400 Received: from localhost by e16.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 24 Jul 2018 08:13:08 -0400 From: Yasmin Beatriz Date: Tue, 24 Jul 2018 12:13:04 +0000 Message-Id: <1532434384-12355-1-git-send-email-yasmins@linux.ibm.com> Subject: [Qemu-devel] [PATCH] target/ppc: simplify bcdadd/sub functions List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-ppc@nongnu.org Cc: qemu-devel@nongnu.org, david@gibson.dropbear.id.au, rth@twiddle.net After solving a corner case in bcdsub, this patch simplifies the logic of both bcdadd/sub instructions by removing some unnecessary local flags. Signed-off-by: Yasmin Beatriz --- target/ppc/int_helper.c | 33 +++++++++------------------------ 1 file changed, 9 insertions(+), 24 deletions(-) diff --git a/target/ppc/int_helper.c b/target/ppc/int_helper.c index fa18e6e..b8ac4bb 100644 --- a/target/ppc/int_helper.c +++ b/target/ppc/int_helper.c @@ -2671,16 +2671,14 @@ static int bcd_cmp_mag(ppc_avr_t *a, ppc_avr_t *b) return 0; } -static int bcd_add_mag(ppc_avr_t *t, ppc_avr_t *a, ppc_avr_t *b, int *invalid, +static void bcd_add_mag(ppc_avr_t *t, ppc_avr_t *a, ppc_avr_t *b, int *invalid, int *overflow) { int carry = 0; int i; - int is_zero = 1; for (i = 1; i <= 31; i++) { uint8_t digit = bcd_get_digit(a, i, invalid) + bcd_get_digit(b, i, invalid) + carry; - is_zero &= (digit == 0); if (digit > 9) { carry = 1; digit -= 10; @@ -2689,26 +2687,20 @@ static int bcd_add_mag(ppc_avr_t *t, ppc_avr_t *a, ppc_avr_t *b, int *invalid, } bcd_put_digit(t, digit, i); - - if (unlikely(*invalid)) { - return -1; - } } *overflow = carry; - return is_zero; } -static int bcd_sub_mag(ppc_avr_t *t, ppc_avr_t *a, ppc_avr_t *b, int *invalid, +static void bcd_sub_mag(ppc_avr_t *t, ppc_avr_t *a, ppc_avr_t *b, int *invalid, int *overflow) { int carry = 0; int i; - int is_zero = 1; + for (i = 1; i <= 31; i++) { uint8_t digit = bcd_get_digit(a, i, invalid) - bcd_get_digit(b, i, invalid) + carry; - is_zero &= (digit == 0); if (digit & 0x80) { carry = -1; digit += 10; @@ -2717,14 +2709,9 @@ static int bcd_sub_mag(ppc_avr_t *t, ppc_avr_t *a, ppc_avr_t *b, int *invalid, } bcd_put_digit(t, digit, i); - - if (unlikely(*invalid)) { - return -1; - } } *overflow = carry; - return is_zero; } uint32_t helper_bcdadd(ppc_avr_t *r, ppc_avr_t *a, ppc_avr_t *b, uint32_t ps) @@ -2734,25 +2721,25 @@ uint32_t helper_bcdadd(ppc_avr_t *r, ppc_avr_t *a, ppc_avr_t *b, uint32_t ps) int sgnb = bcd_get_sgn(b); int invalid = (sgna == 0) || (sgnb == 0); int overflow = 0; - int zero = 0; uint32_t cr = 0; ppc_avr_t result = { .u64 = { 0, 0 } }; if (!invalid) { if (sgna == sgnb) { result.u8[BCD_DIG_BYTE(0)] = bcd_preferred_sgn(sgna, ps); - zero = bcd_add_mag(&result, a, b, &invalid, &overflow); - cr = (sgna > 0) ? CRF_GT : CRF_LT; + bcd_add_mag(&result, a, b, &invalid, &overflow); + cr = bcd_cmp_zero(&result); } else if (bcd_cmp_mag(a, b) > 0) { result.u8[BCD_DIG_BYTE(0)] = bcd_preferred_sgn(sgna, ps); - zero = bcd_sub_mag(&result, a, b, &invalid, &overflow); + bcd_sub_mag(&result, a, b, &invalid, &overflow); cr = (sgna > 0) ? CRF_GT : CRF_LT; } else if (bcd_cmp_mag(a, b) == 0) { result.u8[BCD_DIG_BYTE(0)] = bcd_preferred_sgn(0, ps); - zero = bcd_sub_mag(&result, b, a, &invalid, &overflow); + bcd_sub_mag(&result, b, a, &invalid, &overflow); + cr = CRF_EQ; } else { result.u8[BCD_DIG_BYTE(0)] = bcd_preferred_sgn(sgnb, ps); - zero = bcd_sub_mag(&result, b, a, &invalid, &overflow); + bcd_sub_mag(&result, b, a, &invalid, &overflow); cr = (sgnb > 0) ? CRF_GT : CRF_LT; } } @@ -2762,8 +2749,6 @@ uint32_t helper_bcdadd(ppc_avr_t *r, ppc_avr_t *a, ppc_avr_t *b, uint32_t ps) cr = CRF_SO; } else if (overflow) { cr |= CRF_SO; - } else if (zero) { - cr = CRF_EQ; } *r = result; -- 1.8.3.1