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Use backtick code blocks for syntax highlighting

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James Gregory 2013-12-31 11:38:48 +11:00
commit f658bfbb40
203 changed files with 26546 additions and 25801 deletions
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70
11-03.md
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@ -101,23 +101,25 @@ refresh.
**LISTING 11.2 L11-2.ASM**
;
; *** Listing 11.2 ***
;
; Measures the performance of accesses to word-sized
; variables that start at odd addresses (are not
; word-aligned).
;
Skip:
push ds
pop es
mov si,1 ;source and destination are the same
mov di,si ; and both are not word-aligned
mov cx,1000 ;move 1000 words
cld
call ZTimerOn
rep movsw
call ZTimerOff
```nasm
;
; *** Listing 11.2 ***
;
; Measures the performance of accesses to word-sized
; variables that start at odd addresses (are not
; word-aligned).
;
Skip:
push ds
pop es
mov si,1 ;source and destination are the same
mov di,si ; and both are not word-aligned
mov cx,1000 ;move 1000 words
cld
call ZTimerOn
rep movsw
call ZTimerOff
```
On the other hand, Listing 11.3, which is exactly the same as Listing
11.2 save that the memory accesses are word-aligned (start at even
@ -128,22 +130,24 @@ we predicted.
**LISTING 11.3 L11-3.ASM**
;
; *** Listing 11.3 ***
;
; Measures the performance of accesses to word-sized
; variables that start at even addresses (are word-aligned).
;
Skip:
push ds
pop es
sub si,si ;source and destination are the same
mov di,si ; and both are word-aligned
mov cx,1000 ;move 1000 words
cld
call ZTimerOn
rep movsw
call ZTimerOff
```nasm
;
; *** Listing 11.3 ***
;
; Measures the performance of accesses to word-sized
; variables that start at even addresses (are word-aligned).
;
Skip:
push ds
pop es
sub si,si ;source and destination are the same
mov di,si ; and both are word-aligned
mov cx,1000 ;move 1000 words
cld
call ZTimerOn
rep movsw
call ZTimerOff
```
The data alignment cycle-eater has intriguing implications for speeding
up 286/386 code. The expenditure of a little care and a few bytes to