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Файл:Carter P.A.PC assembly language.2005.pdf
42 |
CHAPTER 2. BASIC ASSEMBLY LANGUAGE |
sum = 0;
for ( i=10; i >0; i−− ) sum += i;
could be translated into assembly as:
1 |
mov |
eax, |
0 |
; |
eax |
is |
sum |
2 |
mov |
ecx, |
10 |
; |
ecx |
is |
i |
3loop_start:
4 |
add |
eax, ecx |
5loop loop_start
2.3Translating Standard Control Structures
This section looks at how the standard control structures of high level languages can be implemented in assembly language.
2.3.1If statements
The following pseudo-code:
if ( condition ) then block ;
else
else block ;
could be implemented as:
1; code to set FLAGS
2 |
jxx |
else_block |
; select xx so that branches if condition false |
3; code for then block
4 |
jmp |
endif |
5else_block:
6; code for else block
7endif:
If there is no else, then the else block branch can be replaced by a branch to endif.
1
2
3
; code |
to set FLAGS |
|
jxx |
endif |
; select xx so that branches if condition false |
; code |
for then block |
|
4endif: