[PATCH] ftrace: simplify hex print

[PATCH] ftrace: simplify hex print

[Thomas Gleixner]

simplify hex to ascii conversion with a lookup table.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

---
 kernel/trace/trace.c |   23 +++++------------------
 1 file changed, 5 insertions(+), 18 deletions(-)

Index: linux/kernel/trace/trace.c
===================================================================
--- linux.orig/kernel/trace/trace.c
+++ linux/kernel/trace/trace.c
@@ -248,19 +248,18 @@ trace_seq_putmem(struct trace_seq *s, vo
 }
 
 #define HEX_CHARS 17
+static const char hex2asc[] = "0123456789abcdef";
 
 static int
 trace_seq_putmem_hex(struct trace_seq *s, void *mem, size_t len)
 {
 	unsigned char hex[HEX_CHARS];
-	unsigned char *data;
+	unsigned char *data = mem;
 	unsigned char byte;
 	int i, j;
 
 	BUG_ON(len >= HEX_CHARS);
 
-	data = mem;
-
 #ifdef __BIG_ENDIAN
 	for (i = 0, j = 0; i < len; i++) {
 #else
@@ -268,22 +267,10 @@ trace_seq_putmem_hex(struct trace_seq *s
 #endif
 		byte = data[i];
 
-		hex[j]   = byte & 0x0f;
-		if (hex[j] >= 10)
-			hex[j] += 'a' - 10;
-		else
-			hex[j] += '0';
-		j++;
-
-		hex[j] = byte >> 4;
-		if (hex[j] >= 10)
-			hex[j] += 'a' - 10;
-		else
-			hex[j] += '0';
-		j++;
+		hex[j++] = hex2asc[byte & 0x0f];
+		hex[j++] = hex2asc[byte >> 4];
 	}
-	hex[j] = ' ';
-	j++;
+	hex[j++] = ' ';
 
 	return trace_seq_putmem(s, hex, j);
 }

Re: [PATCH] ftrace: simplify hex print

[Ingo Molnar]

* Thomas Gleixner <tglx@linutronix.de> wrote:

> simplify hex to ascii conversion with a lookup table.

thanks Thomas, applied.

	Ingo

Re: [PATCH] ftrace: simplify hex print

[Rene Herman]

On 18-04-08 14:35, Ingo Molnar wrote:

> * Thomas Gleixner <tglx@linutronix.de> wrote:
> 
>> simplify hex to ascii conversion with a lookup table.
> 
> thanks Thomas, applied.

There is a hex_asc() in kernel.h

Rene.

Re: [PATCH] ftrace: simplify hex print

[Heiko Carstens]

On Fri, Apr 18, 2008 at 02:33:20PM +0200, Thomas Gleixner wrote:
> simplify hex to ascii conversion with a lookup table.
> 
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> +static const char hex2asc[] = "0123456789abcdef";
[...]
> +		hex[j++] = hex2asc[byte & 0x0f];
> +		hex[j++] = hex2asc[byte >> 4];

we have hex_asc() in include/linux/kernel.h already.

Re: [PATCH] ftrace: simplify hex print

[Andrew Morton]

On Fri, 18 Apr 2008 14:33:20 +0200 (CEST) Thomas Gleixner <tglx@linutronix.de> wrote:

> +static const char hex2asc[] = "0123456789abcdef";

43.