Data update

Task/Twos-complement/8080-Assembly/twos-complement.8080

@@ -0,0 +1,28 @@
+org 100h    ; program load point under CP/M
+    ;
+    ; the assembler itself will negate an
+    ; 8 or 16-bit constant for us
+    ;
+mvi a,-43   ; a = D5
+lxi h,-43   ; hl = FFD5
+    ;
+    ; no built-in opcode to negate an 8-bit
+    ; register, but nevertheless easily done
+    ;
+mvi a,43    ; a = 2B
+cma
+inr a       ; a = D5
+    ;
+    ; the same approach for 16-bit values
+    ;
+lxi h,43    ; hl = 002B
+mov a,l
+cma
+mov l,a
+mov a,h
+cma
+mov h,a
+inx h       ; hl = FFD5
+    ;
+jmp 0       ; exit to CP/M
+end