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Date: Mon, 7 Feb 2022 17:23:37 +0100
From: Willy Tarreau <w@....eu>
To: "Paul E . McKenney" <paulmck@...nel.org>
Cc: Mark Brown <broonie@...nel.org>, linux-kernel@...r.kernel.org,
Willy Tarreau <w@....eu>
Subject: [PATCH 25/42] tools/nolibc/stdlib: avoid a 64-bit shift in u64toh_r()
The build of printf() on mips requires libgcc for functions __ashldi3 and
__lshrdi3 due to 64-bit shifts when scanning the input number. These are
not really needed in fact since we scan the number 4 bits at a time. Let's
arrange the loop to perform two 32-bit shifts instead on 32-bit platforms.
Signed-off-by: Willy Tarreau <w@....eu>
---
tools/include/nolibc/stdlib.h | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)
diff --git a/tools/include/nolibc/stdlib.h b/tools/include/nolibc/stdlib.h
index 82a4cf606d3c..db47362a750f 100644
--- a/tools/include/nolibc/stdlib.h
+++ b/tools/include/nolibc/stdlib.h
@@ -200,14 +200,18 @@ int u64toh_r(uint64_t in, char *buffer)
int dig;
do {
- dig = in >> pos;
- in -= (uint64_t)dig << pos;
+ if (sizeof(long) >= 8) {
+ dig = (in >> pos) & 0xF;
+ } else {
+ /* 32-bit platforms: avoid a 64-bit shift */
+ uint32_t d = (pos >= 32) ? (in >> 32) : in;
+ dig = (d >> (pos & 31)) & 0xF;
+ }
+ if (dig > 9)
+ dig += 'a' - '0' - 10;
pos -= 4;
- if (dig || digits || pos < 0) {
- if (dig > 9)
- dig += 'a' - '0' - 10;
+ if (dig || digits || pos < 0)
buffer[digits++] = '0' + dig;
- }
} while (pos >= 0);
buffer[digits] = 0;
--
2.35.1
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