Modern Computer Architecture and Organization, by Jim Ledin. Published by Packt Publishing.
Write an x86 assembly language program that computes the following expression and prints the result as a hexadecimal number: {(129 – 66) × (445 + 136)} ÷ 3. As part of this program, create a callable function to print one byte as two hex digits.
Create your assembly language source file. See Ex__2_expr_x86.asm for an example solution to this exercise.
Open the x86 Native Tools Command Prompt for VS 2019 and change to the directory containing your source file.
Build the executable with this command:
ml /Fl /Zi /Zd Ex__2_expr_x86.asm
This is the output produced by the program:
C:\>Ex__2_expr_x86.exe
[(129 - 66) * (445 + 136)] / 3 = 2FA9h
This is the listing file created by the build procedure:
Microsoft (R) Macro Assembler Version 14.23.28107.0 01/26/20 20:45:09
Ex__2_expr_x86.asm Page 1 - 1
.386
.model FLAT,C
.stack 400h
00000000 .code
includelib libcmt.lib
includelib legacy_stdio_definitions.lib
extern printf:near
extern exit:near
public main
00000000 main proc
; Print the leading output string
00000000 68 00000005 R push offset msg1
00000005 E8 00000000 E call printf
; Compute [(129 – 66) * (445 + 136)] / 3
0000000A B8 00000081 mov eax, 129
0000000F 83 E8 42 sub eax, 66
00000012 BB 000001BD mov ebx, 445
00000017 81 C3 00000088 add ebx, 136
0000001D 66| F7 E3 mul bx
00000020 66| BB 0003 mov bx, 3
00000024 66| F7 F3 div bx
; Print the most significant byte
00000027 50 push eax
00000028 8A DC mov bl, ah
0000002A E8 00000017 call print_byte
; Print the least significant byte
0000002F 5B pop ebx
00000030 E8 00000011 call print_byte
; Print the trailing output string
00000035 68 00000027 R push offset msg2
0000003A E8 00000000 E call printf
0000003F 6A 00 push 0
00000041 E8 00000000 E call exit
00000046 main endp
; Pass the byte to be printed in ebx
00000046 print_byte proc
; x86 function prologue
00000046 55 push ebp
00000047 8B EC mov ebp, esp
; Use the C library printf function
00000049 81 E3 000000FF and ebx, 0ffh
0000004F 53 push ebx
00000050 68 00000000 R push offset fmt_str
00000055 E8 00000000 E call printf
; x86 function epilogue
0000005A 8B E5 mov esp, ebp
0000005C 5D pop ebp
0000005D C3 ret
0000005E print_byte endp
00000000 .data
00000000 25 30 32 58 00 fmt_str db "%02X", 0
00000005 5B 28 31 32 39 msg1 db "[(129 - 66) * (445 + 136)] / 3 = ", 0
20 2D 20 36 36
29 20 2A 20 28
34 34 35 20 2B
20 31 33 36 29
5D 20 2F 20 33
20 3D 20 00
00000027 68 09 msg2 db "h", 9
end
Microsoft (R) Macro Assembler Version 14.23.28107.0 01/26/20 20:45:09
Ex__2_expr_x86.asm Symbols 2 - 1
Segments and Groups:
N a m e Size Length Align Combine Class
FLAT . . . . . . . . . . . . . . GROUP
STACK . . . . . . . . . . . . . 32 Bit 00000400 DWord Stack 'STACK'
_DATA . . . . . . . . . . . . . 32 Bit 00000029 DWord Public 'DATA'
_TEXT . . . . . . . . . . . . . 32 Bit 0000005E DWord Public 'CODE'
Procedures, parameters, and locals:
N a m e Type Value Attr
main . . . . . . . . . . . . . . P Near 00000000 _TEXT Length= 00000046 Public C
print_byte . . . . . . . . . . . P Near 00000046 _TEXT Length= 00000018 Public C
Symbols:
N a m e Type Value Attr
@CodeSize . . . . . . . . . . . Number 00000000h
@DataSize . . . . . . . . . . . Number 00000000h
@Interface . . . . . . . . . . . Number 00000001h
@Model . . . . . . . . . . . . . Number 00000007h
@code . . . . . . . . . . . . . Text _TEXT
@data . . . . . . . . . . . . . Text FLAT
@fardata? . . . . . . . . . . . Text FLAT
@fardata . . . . . . . . . . . . Text FLAT
@stack . . . . . . . . . . . . . Text FLAT
exit . . . . . . . . . . . . . . L Near 00000000 FLAT External C
fmt_str . . . . . . . . . . . . Byte 00000000 _DATA
msg1 . . . . . . . . . . . . . . Byte 00000005 _DATA
msg2 . . . . . . . . . . . . . . Byte 00000027 _DATA
printf . . . . . . . . . . . . . L Near 00000000 FLAT External C
0 Warnings
0 Errors