isa/examples: code fixes

diff --git a/2_isa/src/bittwiddling.c b/2_isa/src/bittwiddling.c
index 65c6349796d8ed6327a6ff365d4cc825dac46dca..9488e8833523abd5663095ca6b79a1f33ef456c5 100644 (file)
--- 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 6a2adb17b1fad4cea950ae6be0d49eb9389cd673..53861d5b8769883b193efe09c937e2bf0044d775 100644 (file)
--- 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 254faed0073fd6e62ef4e26863edb72feb89f9d7..58a678cd10efbd4c7f29fafb1d4cf5ff812a2ecd 100644 (file)
--- 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 6732e260d62d200263044b6d5acfac429d24da64..98d6df34a22f0bfe7f9f15cb4ac3da0fc0897122 100644 (file)
--- 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 e0656737b01ffc1b4fd85caf4784ba4ac90ccb3c..b1d0685413b96523bd4939aff4ee0187c250373a 100755 (executable)
--- 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 8094db351b2ca6fdea20368163c0292303af00ff..1aa4051d926b399928683f158d46692a396a8976 100755 (executable)
--- 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 (file)
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 ab2682fd8170263345e4896993507ca994456aaa..f4bce89eef6c78dbd9ecfd50df87ac51be88ff99 100644 (file)
--- 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   ;