diff options
| author | Nicolas Pitre <npitre@baylibre.com> | 2024-10-03 17:16:15 -0400 |
|---|---|---|
| committer | Arnd Bergmann <arnd@arndb.de> | 2024-10-28 21:44:28 +0000 |
| commit | 06508533d51a1dc96c5399e533adfe9ec1076088 (patch) | |
| tree | c3b5e713fc8f4f8d990e59a11d9e65d799b928ad /arch/arm/include/asm/div64.h | |
| parent | 00a31dd3acea0f88f947fc71e268ebb34b59f218 (diff) | |
ARM: div64: improve __arch_xprod_64()
Let's use the same criteria for overflow handling necessity as the
generic code.
Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Diffstat (limited to 'arch/arm/include/asm/div64.h')
| -rw-r--r-- | arch/arm/include/asm/div64.h | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/arch/arm/include/asm/div64.h b/arch/arm/include/asm/div64.h index 4b69cf850451..562d5376ae7a 100644 --- a/arch/arm/include/asm/div64.h +++ b/arch/arm/include/asm/div64.h @@ -56,6 +56,8 @@ static inline uint64_t __arch_xprod_64(uint64_t m, uint64_t n, bool bias) { unsigned long long res; register unsigned int tmp asm("ip") = 0; + bool no_ovf = __builtin_constant_p(m) && + ((m >> 32) + (m & 0xffffffff) < 0x100000000); if (!bias) { asm ( "umull %Q0, %R0, %Q1, %Q2\n\t" @@ -63,7 +65,7 @@ static inline uint64_t __arch_xprod_64(uint64_t m, uint64_t n, bool bias) : "=&r" (res) : "r" (m), "r" (n) : "cc"); - } else if (!(m & ((1ULL << 63) | (1ULL << 31)))) { + } else if (no_ovf) { res = m; asm ( "umlal %Q0, %R0, %Q1, %Q2\n\t" "mov %Q0, #0" @@ -80,7 +82,7 @@ static inline uint64_t __arch_xprod_64(uint64_t m, uint64_t n, bool bias) : "cc"); } - if (!(m & ((1ULL << 63) | (1ULL << 31)))) { + if (no_ovf) { asm ( "umlal %R0, %Q0, %R1, %Q2\n\t" "umlal %R0, %Q0, %Q1, %R2\n\t" "mov %R0, #0\n\t" |