From: Bernhard Urban <lewurm@gmail.com>
Date: Thu, 28 Oct 2010 10:45:47 +0000 (+0200)
Subject: isa/examples: code fixes
X-Git-Tag: bootrom_v1~240
X-Git-Url: http://wien.tomnetworks.com/gitweb/?p=calu.git;a=commitdiff_plain;h=ed680dd42d0e4b6ac162cdbd801348d86a77f18d

isa/examples: code fixes
---

diff --git a/2_isa/src/bittwiddling.c b/2_isa/src/bittwiddling.c
index 65c6349..9488e88 100644
--- a/2_isa/src/bittwiddling.c
+++ b/2_isa/src/bittwiddling.c
@@ -1,4 +1,3 @@
-
 #define B0 (0x55555555)
 #define B1 (0x33333333)
 #define B2 (0x0F0F0F0F)
@@ -14,17 +13,3 @@ int countbits(int x) {
 	x = (x + (x >> 16)) & B4;
 	return x;
 }
-
-int computeparity(int x) 
-	x ^= x >> 16;
-	x ^= x >> 8;
-	x ^= x >> 4;
-	x &= 0xf;
-	return (0x6996 >> x) & 1;
-}
-
-void main(void) {
-	countbits(B0);
-	computeparity(B0);
-	computeparity(B0+1);
-}
diff --git a/2_isa/src/bittwiddling.s b/2_isa/src/bittwiddling.s
index 6a2adb1..53861d5 100644
--- a/2_isa/src/bittwiddling.s
+++ b/2_isa/src/bittwiddling.s
@@ -1,21 +1,9 @@
-
 .data
-.align 32
-;#define B0 (0x55555555)
-B0:
-.dw 0x55555555
-;#define B1 (0x33333333)
-B1:
-.dw 0x33333333
-;#define B2 (0x0F0F0F0F)
-B2:
-.dw 0x0F0F0F0F
-;#define B3 (0x001F001F)
-B3:
-.dw 0x001F001F
-;#define B4 (0x0000003F)
-B4:
-.dw 0x0000003F
+B0: .fill 0x55555555
+B1: .fill 0x33333333
+B2: .fill 0x0F0F0F0F
+B3: .fill 0x001F001F
+B4: .fill 0x0000003F
 
 .text
 
@@ -24,15 +12,15 @@ countbits:
 	;x == r1
 	
 	;load address of B0 into r3
-	ldil r3,low(B0);
-	ldih r3,high(B0);
+	ldil r3, B0@lo;
+	ldih r3, B0@hi;
 
 	;x = (x & B0) + ((x >>  1) & B0);
 	;r0 = (x >> 1)
 	lrs r0,r1,1;
 	
 	;load B0 into r2
-	ldx r2, r3;
+	ldw r2, 0(r3);
 
 	;(x >> 1) & B0	
 	and r0, r0, r2;
@@ -44,30 +32,27 @@ countbits:
 	add r0, r0, r1;
 
 	;load B1 into r2, use displacment for address of B1 (or add?)
-	ldx r2, (r3)(B1-B0);
+	ldw r2, B1-B0(r3);
 
 	;x = (x & B1) + ((x >>  2) & B1);
 	lrs r1, r0, 2;
 	and r1, r1, r2;
-
 	and r0, r0, r2;
-
 	add r0, r0, r1;
 
 	;x = (x + (x >>  4)) & B2;
-	ldx r2, (r3)(B2-B0);
+	ldw r2, B2-B0(r3);
 
 	lrs r1, r0, 4;
 	and r1, r1, r2;
 	and r0, r0, r2;
-
 	add r0, r0, r1;
 
 	;x = (x + (x >>  8)) /*& B3 */
 	lrs r1, r0, 8;
 	add r0, r0, r1;
 
-	ldx r2, (r3)(B4-B0);
+	ldw r2, B4-B0(r3);
 	;x = (x + (x >> 16)) & B4;
 	lrs r1, r0, 16;
 	add r0, r0, r1;
@@ -76,17 +61,3 @@ countbits:
 	;return x;
 	ret;
 ;}
-
-int computeparity(int x) 
-	x ^= x >> 16;
-	x ^= x >> 8;
-	x ^= x >> 4;
-	x &= 0xf;
-	return (0x6996 >> x) & 1;
-}
-
-void main(void) {
-	countbits(B0);
-	computeparity(B0);
-	computeparity(B0+1);
-}
diff --git a/2_isa/src/bootrom.c b/2_isa/src/bootrom.c
index 254faed..58a678c 100644
--- a/2_isa/src/bootrom.c
+++ b/2_isa/src/bootrom.c
@@ -35,7 +35,6 @@
 #define UART_RECV_NEW 1
 
 /* TODO:
- * - need jump to register value
  * - uart: clear new_receive bit after the byte is copied?
  *   (implementation issue...)
  */
diff --git a/2_isa/src/bootrom.s b/2_isa/src/bootrom.s
index 6732e26..98d6df3 100644
--- a/2_isa/src/bootrom.s
+++ b/2_isa/src/bootrom.s
@@ -59,7 +59,6 @@ send_byte:
 
 ;-----
 send_word:
-	; TODO: loop? (less codesize...)
 	lrs r0, r1, 0
 	call send_byte
 	lrs r0, r1, 8
@@ -102,7 +101,6 @@ recv_word:
 
 	ret
 
-
 ;-----
 bootrom:
 	call recv_byte
diff --git a/2_isa/src/palindrom.c b/2_isa/src/palindrom.c
index e065673..b1d0685 100755
--- a/2_isa/src/palindrom.c
+++ b/2_isa/src/palindrom.c
@@ -3,7 +3,7 @@
 u8 palindrom(u8* str, u8 len) {
 	u8 *str1, *str2;
 	if (len == 0) { 
-		return 0;
+		return 1;
 	}
 	str1 = str; 
 	str2 = str + len - 1;
diff --git a/2_isa/src/palindrom.s b/2_isa/src/palindrom.s
index 8094db3..1aa4051 100755
--- a/2_isa/src/palindrom.s
+++ b/2_isa/src/palindrom.s
@@ -3,21 +3,21 @@
 ; r1 = str addr
 ; r2 = str len (u8)
 
-	ldi r0, 0
-
-	cmp r1, 0
-	retzs		; return 0 if strlen = 0
+	ldis r0, 0
+	cmpi r2, 0
+	ldiszsd r0, 1
+	retzs		; return 1 if strlen = 0
 
 	add  r4, r1, r2 ; set r4 to end address
-	subi r4, 1
+	subi r4, r4, 1
 
 	cmp  r1, r4	; if strlen = 1 return 1
 	brancheq- end
 
 schleife:
 
-	ldb  r5, r1
-	ldb  r6, r4
+	ldb  r5, 0(r1)
+	ldb  r6, 0(r4)
 
 	cmp  r5, r6
 	retnq		; return 0 when palindrom not satisfied
diff --git a/2_isa/src/strncmp.c b/2_isa/src/strncmp.c
new file mode 100644
index 0000000..2f9b333
--- /dev/null
+++ b/2_isa/src/strncmp.c
@@ -0,0 +1,10 @@
+int strncmp(const uint8_t *b1, const uint8_t *b2, size_t len)
+{
+	int diff=0;
+	
+	for (;len && (*b1) && (*b2) && !(diff); --len) {
+		diff = b1++ - b2++;
+	}
+
+	return diff;
+}
diff --git a/2_isa/src/strncmp.s b/2_isa/src/strncmp.s
index ab2682f..f4bce89 100644
--- a/2_isa/src/strncmp.s
+++ b/2_isa/src/strncmp.s
@@ -1,35 +1,22 @@
-int strncmp(const uint8_t *b1, const uint8_t *b2, size_t len)
-{
-	int diff=0;
-	
-
-	for (;len && (*b1) && (*b2) && !(diff); --len) {
-		diff = b1[i] - b2[i];
-	}
-
-	return diff;
-}
-
-
-strncmp.s:
+strncmp:
 
 ldis r5, 0      ;
 
-:strfor
+strfor:
 ldis r0, 0      ;
-ldb r0, r1      ; r0 = (*b1)
-ldb r5, r2      ; r5 = (*b2)
-addi r3, 0      ; len == 0
-addinq r0, 0    ; (*b1) == 0
-addinq r5, 0    ; (*b2) == 0
+ldb r0, 0(r1)   ; r0 = (*b1)
+ldb r5, 0(r2)   ; r5 = (*b2)
+cmpi r3, 0      ; len == 0
+cmpinq r0, 0    ; (*b1) == 0
+cmpinq r5, 0    ; (*b2) == 0
 
 ldiseq r0,0     ;    
 reteq           ;
 
 sub r0, r0, r5  ; diff = (*b1)-(*b2)
-addi r0,0       ; diff!=0
+cmpi r0, 0      ; diff!=0
 retnq           ;
-addi r1,1       ; ++b1
-addi r2,1       ; ++b2
-subi r3,1       ; ++len
+addi r1, r1 ,1  ; ++b1
+addi r2, r2, 1  ; ++b2
+subi r3, r3, 1  ; --len
 branch strfor   ;