整數運算
- 加法
- 加法指令
add source, destination - 示例
- 加法指令
# addtest1.s - An example of the ADD instruction
.section .data
data:
.int 40
.section
.globl _start
_start:
nop
movl $0, %eax
movl $0, %ebx
movl $0, %ecx
movb $20, %al
addb $10, %al
movsx %al, %eax
movw $100, %cx
addw %cx, %bx
movsx %bx, %ebx
movl $100, %edx
addl %edx, %edx
addl data, %eax
addl %eax, data
movl $1, %eax
movl $0, %ebx
int $0x80
- 發現一個進位或者溢出
- 示例
# addrest.s - An example of detecting a carry condition
.section .text
.globl _start
_start:
nop
movl $0, %eax
movb $190, %bl
movb $100, %al
addb %al, %bl
jc over
movl $1, %eax
int $0x80
over:
movl $1, %eax
movl $0, %ebx
int $0x80
* ADC 指令
* 格式
adc source, destination
* 示例
# addtest.s - An example of using the ADC instruction
.section .data
data1:
.quad 7252051615
data2:
.quad 5732348928
output:
.asciz "The result is %qd\n"
.section .text
.globl _start
_start:
movl data1, %ebx
movl data1+4, %eax
movl data2, %edx
movl data2+4, %ecx
addl %ebx, edx
adcl %eax, %ecx
pushl %ecx
pushl %edx
push $output
call printf
add $12, %esp
pushl $0
call exit
- 減法
- 減法指令
- 格式
sub source, destionation - 示例
- 格式
- 減法指令
# subtest.s - An example of the SUB instruction
.section .data
data:
.int 40
.section .text
.globl _start
_start:
nop
movl $0, %eax
movl $0, %ebx
movl $0, %ecx
movb $20, %al
subb $10, %al
movsx %al, %eax
movw $100, %cx
subw %cx, %bx
movsx %bx, %ebx
movl $100, %edx
subl %eax, %edx
subl data, %eax
subl %eax, data
movl $1, %eax
movl $0, %ebx
int $0x80
* 減法的進位和溢出標誌
* 示例
# subtest.s - An example of a subtraction carry
.section .text
.globl _start
_start:
nop
movl $5, %eax
movl $2, %ebx
subl %eax, %ebx
jc under
movl $1, %eax
int $0x80
under:
movl $1, %eax
movl $0, %ebx
int $0x80
* SBB 指令
* 標誌
sbb source, destiantion
* 示例
# sbbtest.s - An example of using the SBB instruction
.section .data
data1:
.quad 7252051615
data2:
.quad 5732348928
output:
.asciz "The result is %qd\n"
.section .text
.globl _start
_start:
nop
movl data1, %ebx
movl data1+4, %eax
movl data2, %edx
movl data2+4, %ecx
subl %ebx, %edx
sbbl %eax, %ecx
pushl %ecx
pushl %edx
push $output
call printf
add $12, %esp
push $0
call exit
* 加一和減一指令
* 格式
dec destionation
inc destionation
- 乘法
- 無符號乘法
- 格式
mul source
- 格式
- 無符號乘法
| 源操作數大小 | 目的操作數 | 結果存放 |
|---|---|---|
| 8 bits | AL | AX |
| 16 bits | AX | DX:AX |
| 32 bits | EAX | EDX:EAX |
* 示例
# multest.s - An example of using the MUL instruction
.section .data
data1:
.int 315814
data2:
.int 165432
result:
.quad 0
output:
.asciz "The result is %qd\n"
.section .text
.globl _start
_start:
nop
movl data1, %eax
mull data2
movl %eax, result
movl %edx, result+4
pushl %edx
pushl %eax
pushl $output
call printf
add $12, %esp
pushl $0
call exit
* 有符號整數乘法
* 格式
imul source
imul source, destination
imul multiplier, source, destionation
* 示例
# imultest.s - An example of the IMUL instruction formats
.section .data
value1:
.int 10
value2:
.int -35
value3:
.int 400
.section .text
.globl _start
_start:
nop
movl value1, %ebx
movl value2, %ecx
imull %ebx, %ecx
movl $1, %eax
movl $0, %ebx
int $0x80
* 發現溢出
# imultest. s - An example of detecting an IMUL overflow
.section .text
.globl _start
_start:
nop
movw $680, %ax
movw $100, %cx
imulw %cx
jo over
movl $1, %eax
movl $0, %ebx
int $0x80
over:
movl $1, %eax
movl $1, %ebx
int $0x80
- 除法
- 無符號除法
- 格式
div divisor
- 格式
- 無符號除法
| 被除數 | 大小 | 商 | 餘數 |
|---|---|---|---|
| AX | 16 bits | AL | AH |
| DX:AX | 32 bits | AX | DX |
| EDX:EAX | 64 bits | EAX | EDX |
* 示例
# divtest.s - An example of the DIV instruction
.section .data
dividend:
.quad 8335
divisor:
.int 25
quotient:
.int 0
remainder:
.int 0
output:
.asciz "The quotient is %d, and the remainder is %d\n"
.section .text
.globl _start
_start:
nop
movl dividend, %eax
movl dividend+4, %edx
divl divisor
movl %eax, quotient
movl %edx, remainder
pushl remainder
pushl quotient
pushl $output
call printf
add $12, %esp
pushl $0
call exit
* 有符號除法
* 格式
idiv divisor
移位運算
- 通過移位進行乘法運算
- 格式
sal destination
sal %cl, destination
sal shifter, destination - 示例
- 格式
# saltest.s - An example of the SAL instruction
.section .data
value1:
.int 25
.section .text
.globl _start
_start:
nop
movl $10, %ebx
sall %ebx
movb $2, %cl
sall %cl, %ebx
sall $2, %ebx
sall value1
sall $2, value1
movl $1, %eax
movl $0, %ebx
int $0x80
- 通過移位進行除法運算
- 格式
SAR （使用符號位）
SHR （使用0）
- 格式
- 循環移位
| 指令 | 描述 |
|---|---|
| ROL | 循環左移 |
| ROR | 循環右移 |
| RCL | 包含符號位左移 |
| RCR | 包含符號位右移 |
十進制運算
- 非壓縮BCD運算
-
格式
AAA： 調整加法運算的結果
AAS： 調整減法運算的結果
AAM： 調整乘法運算的結果
AAD： 準備除法運算的被除數AAA、AAS、AAM的結果默認放在AL寄存器
AAD默認被除數存放在AX寄存器 -
示例
-
# aaatest.s - An example of using the AAA instruction
.section .data
value1:
.byte 0x05, 0x02, 0x01, 0x08, 0x02
value2:
.byte 0x03, 0x03, 0x09, 0x02, 0x05
.section .bss
.lcomm sum, 6
.section .text
.globl _start
_start:
nop
xor %edi, %edi
movl %5, %ecx
clc
loop1:
movb value1(, %edi, 1), %al
adcb value2(, %edi, 1), %al
aaa
movb %al, sum(, %edi, 1)
inc %edi
loop loop1
adcb $0, sum(, %edi, 4)
movl $1, %eax
movl $0, %ebx
int $0x80
- 壓縮BCD運算
- 格式
DAA 調整的ADD或ADC的結果
DAS 調整SUB或SBB的結果 - 示例
- 格式
# dastest.s - An example of using the DAS instruction
.section .data
value1:
.byte 0x25, 0x81, 0x02
value2:
.byte 0x33, 0x29, 0x05
.section .bss
.lcomm result, 4
.section .text
.globle _start
_start:
nop
xor %edi, %edi
movl $3, %ecx
loop1:
movb value2(, %edi, 1), %al
sbbb value1(, %edi, 1), %al
das
movb %al, result(, %edi, 1)
inc %edi
loop loop1
sbbb $0, result(, %edi, 4)
movl $1, %eax
movl $0, %ebx
int $0x80
邏輯運算
- 布爾運算
- AND
- NOT
- OR
- XOR
- 位測試
- 示例
# cpuidtest.s - An example of using the TEST instruction
.section .data
output_cpuid:
.asciz "This processor supports the CPUID instruction\n"
output_nocpuid:
.asciz "This processor does not support the CPUID instruction\n"
.section .text
.globl _start
_start:
nop
pushfl
popl %eax
movl %eax, %edx
xor $00200000, %eax
pushl %eax
popfl
pushfl
popl %eax
xor %edx, %eax
test $00200000, %eax
jnz cpuid
pushl $output_nocpuid
call printf
add $4, %esp
pushl $0
call exit
cpuid:
pushl $output_cpuid
call printf
add $4, %esp
pushl $0
call exit