print_buffer: optimize & shrink

Applying a little creative format string allows us to shrink the initial data read & display loop by only calling printf once. Re-using the local data buffer to generate the string we want to display then allows us to output everything with just one printf call instead of multiple calls to the putc function. The local stack buffer needs increasing by 1 byte, but the resulting code shrink and speed up is worth it I think. Signed-off-by: Mike Frysinger <vapier@gentoo.org>

print_buffer: optimize & shrink
Applying a little creative format string allows us to shrink the initial data read & display loop by only calling printf once. Re-using the local data buffer to generate the string we want to display then allows us to output everything with just one printf call instead of multiple calls to the putc function. The local stack buffer needs increasing by 1 byte, but the resulting code shrink and speed up is worth it I think. Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Mike Frysinger · Wolfgang Denk
1 parent 8faba4894c
Showing 1 changed file with 13 additions and 14 deletions Side-by-side Diff
lib/display_options.c
@@ -101,7 +101,7 @@
 #define DEFAULT_LINE_LENGTH_BYTES (16)
 int print_buffer (ulong addr, void* data, uint width, uint count, uint linelen)
 {
-	uint8_t linebuf[MAX_LINE_LENGTH_BYTES];
+	uint8_t linebuf[MAX_LINE_LENGTH_BYTES + 1];
 	uint32_t *uip = (void*)linebuf;
 	uint16_t *usp = (void*)linebuf;
 	uint8_t *ucp = (void*)linebuf;
  
  
@@ -121,24 +121,23 @@
  
 		/* Copy from memory into linebuf and print hex values */
 		for (i = 0; i < linelen; i++) {
-			if (width == 4) {
-				uip[i] = *(volatile uint32_t *)data;
-				printf(" %08x", uip[i]);
-			} else if (width == 2) {
-				usp[i] = *(volatile uint16_t *)data;
-				printf(" %04x", usp[i]);
-			} else {
-				ucp[i] = *(volatile uint8_t *)data;
-				printf(" %02x", ucp[i]);
-			}
+			uint32_t x;
+			if (width == 4)
+				x = uip[i] = *(volatile uint32_t *)data;
+			else if (width == 2)
+				x = usp[i] = *(volatile uint16_t *)data;
+			else
+				x = ucp[i] = *(volatile uint8_t *)data;
+			printf(" %0*x", width * 2, x);
 			data += width;
 		}
  
 		/* Print data in ASCII characters */
-		puts("    ");
 		for (i = 0; i < linelen * width; i++)
-			putc(isprint(ucp[i]) && (ucp[i] < 0x80) ? ucp[i] : '.');
-		putc ('\n');
+			if (!isprint(ucp[i]) || ucp[i] >= 0x80)
+				ucp[i] = '.';
+		ucp[i] = '\0';
+		printf("    %s\n", ucp);
  
 		/* update references */
 		addr += linelen * width;
...	...	@@ -101,7 +101,7 @@
101	101	#define DEFAULT_LINE_LENGTH_BYTES (16)
102	102	int print_buffer (ulong addr, void* data, uint width, uint count, uint linelen)
103	103	{
104		- uint8_t linebuf[MAX_LINE_LENGTH_BYTES];
	104	+ uint8_t linebuf[MAX_LINE_LENGTH_BYTES + 1];
105	105	uint32_t uip = (void)linebuf;
106	106	uint16_t usp = (void)linebuf;
107	107	uint8_t ucp = (void)linebuf;
108	108
109	109
...	...	@@ -121,24 +121,23 @@
121	121
122	122	/* Copy from memory into linebuf and print hex values */
123	123	for (i = 0; i < linelen; i++) {
124		- if (width == 4) {
125		- uip[i] = (volatile uint32_t )data;
126		- printf(" %08x", uip[i]);
127		- } else if (width == 2) {
128		- usp[i] = (volatile uint16_t )data;
129		- printf(" %04x", usp[i]);
130		- } else {
131		- ucp[i] = (volatile uint8_t )data;
132		- printf(" %02x", ucp[i]);
133		- }
	124	+ uint32_t x;
	125	+ if (width == 4)
	126	+ x = uip[i] = (volatile uint32_t )data;
	127	+ else if (width == 2)
	128	+ x = usp[i] = (volatile uint16_t )data;
	129	+ else
	130	+ x = ucp[i] = (volatile uint8_t )data;
	131	+ printf(" %0x", width 2, x);
134	132	data += width;
135	133	}
136	134
137	135	/* Print data in ASCII characters */
138		- puts(" ");
139	136	for (i = 0; i < linelen * width; i++)
140		- putc(isprint(ucp[i]) && (ucp[i] < 0x80) ? ucp[i] : '.');
141		- putc ('\n');
	137	+ if (!isprint(ucp[i]) \|\| ucp[i] >= 0x80)
	138	+ ucp[i] = '.';
	139	+ ucp[i] = '\0';
	140	+ printf(" %s\n", ucp);
142	141
143	142	/* update references */
144	143	addr += linelen * width;