Ethiopian multiplication: Difference between revisions

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     stp x1,lr,[sp,-16]!        // save  registers
     stp x2,x3,[sp,-16]!        // save  registers
-    stp x4,x5,[sp,-16]!        // save  registers
     mov x2,#0                  // init result
 :                            // loop
@@ Line 221: / Line 220: @@
     blt 3f
     ands x3,x0,#1              //
-    add x4,x2,x1               // add factox2 to result
+    add x3,x2,x1               // add factor2 to result
-    csel x2,x2,x4,eq
+    csel x2,x2,x3,eq
+    mov x3,1
+    lsr x0,x0,x3               // divide factor1 by 2
+    cmp x1,0                  // overflow ? if bit 63 = 1 ie negative number
+    blt 2f
     mov x4,1
-    lsr x0,x0,x4               // divide factox1 by 2
+    lsl x1,x1,x4               // multiply factor2 by 2
-    mov x4,1<63
-    and x5,x1,x4
-    cmp x5,x4                  // overflow ?
-    beq 2f
-    mov x4,1
-    lsl x1,x1,x4               // multiply factox2 by 2
     b 1b                       // or loop
 :                            // error display