sh: use the common ascii hex helpers

index 832641b..bf8ac4c 100644
@@ -274,8 +274,7 @@ static char *mem_to_hex(const char *mem, char *buf, const int count)
 	}
 	for (i = 0; i < count; i++) {
 		ch = *mem++;
-		*buf++ = highhex(ch);
-		*buf++ = lowhex(ch);
+		buf = pack_hex_byte(buf, ch);
 	}
 	*buf = 0;
 	return (buf);

@@ -427,8 +426,8 @@ static void put_packet(char *buffer)
 
 		/* '#' Separator, put high and low components of checksum */
 		put_debug_char('#');
-		put_debug_char(highhex(checksum));
-		put_debug_char(lowhex(checksum));
+		put_debug_char(hex_asc_hi(checksum));
+		put_debug_char(hex_asc_lo(checksum));
 	}
 	while ((get_debug_char()) != '+');	/* While no ack */
 }

@@ -650,8 +649,8 @@ static void undo_single_step(void)
 static void send_signal_msg(const int signum)
 {
 	out_buffer[0] = 'S';
-	out_buffer[1] = highhex(signum);
-	out_buffer[2] = lowhex(signum);
+	out_buffer[1] = hex_asc_hi(signum);
+	out_buffer[2] = hex_asc_lo(signum);
 	out_buffer[3] = 0;
 	put_packet(out_buffer);
 }

index 8fdafc2..ce6ee92 100644
@@ -184,15 +184,15 @@ static void put_string(struct sci_port *sci_port, const char *buffer, int count)
 			int h, l;
 
 			c = *p++;
-			h = highhex(c);
-			l = lowhex(c);
+			h = hex_asc_hi(c);
+			l = hex_asc_lo(c);
 			put_char(port, h);
 			put_char(port, l);
 			checksum += h + l;
 		}
 		put_char(port, '#');
-		put_char(port, highhex(checksum));
-		put_char(port, lowhex(checksum));
+		put_char(port, hex_asc_hi(checksum));
+		put_char(port, hex_asc_lo(checksum));
 	    } while  (get_char(port) != '+');
 	} else
 #endif /* CONFIG_SH_STANDARD_BIOS || CONFIG_SH_KGDB */

index 4bc8cb1..24e4207 100644
@@ -66,18 +66,4 @@ extern int     setjmp(jmp_buf __jmpb);
 /* Forced breakpoint */
 #define breakpoint()	__asm__ __volatile__("trapa   #0x3c")
 
-/* Taken from sh-stub.c of GDB 4.18 */
-static const char hexchars[] = "0123456789abcdef";
-
-/* Get high hex bits */
-static inline char highhex(const int x)
-{
-	return hexchars[(x >> 4) & 0xf];
-}
-
-/* Get low hex bits */
-static inline char lowhex(const int x)
-{
-	return hexchars[x & 0xf];
-}
 #endif