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13-04.md

@@ -17,7 +17,9 @@ register may serve as the base memory addressing register, and almost
 any register may serve as the potentially scaled index register. For
 example,
 
-    mov al,BaseTable[ecx+edx*4]
+```nasm
+mov al,BaseTable[ecx+edx*4]
+```
 
 uses a perfectly valid 32-bit address, with the byte accessed being the
 one at the offset in DS pointed to by the sum of EDX times 4 plus the
@@ -82,21 +84,25 @@ registers when they're needed, but if you find yourself using them
 inside key loops, you should see if it's possible to move the index
 calculation outside the loop as, for example, in a loop like this:
 
-    LoopTop:
-          add   ax,DataTable[ebx*2]
-          inc   ebx
-          dec   cx
-          jnz   LoopTop
+```nasm
+LoopTop:
+      add   ax,DataTable[ebx*2]
+      inc   ebx
+      dec   cx
+      jnz   LoopTop
+```
 
 You could change this to the following for greater performance:
 
-          add   ebx,ebx      ;ebx*2
-    LoopTop:
-          add   ax,DataTable[ebx]
-          add   ebxX,2
-          dec   cx
-          jnz   LoopTop
-          shr   ebx,1 ;ebx*2/2
+```nasm
+      add   ebx,ebx      ;ebx*2
+LoopTop:
+      add   ax,DataTable[ebx]
+      add   ebxX,2
+      dec   cx
+      jnz   LoopTop
+      shr   ebx,1 ;ebx*2/2
+```
 
 I'll end this chapter with two more quirks of 32-bit addressing. First,
 as with 16-bit addressing, addressing that uses EBP as a base register