アセンブリ ライブラリを使用して、標準入力から 3 つの整数を読み取るプログラムを作成しています。読み取りがコンソールで行われると完全に機能しますが、ファイルを入力として使用すると、3 つの整数が一度に読み取られます。
これはコンソールの strace です:
read(0, "3000\n", 512) = 5
read(0, "2000\n", 512) = 5
read(0, "1000\n", 512) = 5
そして、これは入力ファイルから：
read(0, "3000\n2000\n1000\n", 512) = 15
read(0, "", 512) = 0
read(0, "", 512) = 0
手順は次のとおりです。
;--------------------------------------------------------
ReadInt:
;
; Reads a 32-bit signed decimal integer from standard
; input, stopping when the Enter key is pressed.
; All valid digits occurring before a non-numeric character
; are converted to the integer value. Leading spaces are
; ignored, and an optional leading + or - sign is permitted.
; All spaces return a valid integer, value zero.
; Receives: nothing
; Returns: If CF=0, the integer is valid, and EAX = binary value.
; If CF=1, the integer is invalid and EAX = 0.
;--------------------------------------------------------
push edx
push ecx
; Input a signed decimal string.
mov edx,digitBuffer
mov ecx,MAX_DIGITS
call ReadString
mov ecx,eax ; save length in ECX
; Convert to binary (EDX -> string, ECX = length)
call ParseInteger32 ; returns EAX, CF
pop ecx
pop edx
ret
;--------------- End of ReadInt ------------------------
;--------------------------------------------------------
ReadString:
;
; Reads a string from the keyboard and places the characters
; in a buffer.
; Receives: EDX offset of the input buffer
; ECX = maximum characters to input (including terminal null)
; Returns: EAX = size of the input string.
; Comments: Stops when Enter key (0Dh,0Ah) is pressed. If the user
; types more characters than (ECX-1), the excess characters
; are ignored.
; Written by Kip Irvine and Gerald Cahill
; Modified by Curtis Wong
;--------------------------------------------------------
enter 8, 0 ; bufSize: ebp - 4
; bytesRead: ebp - 8
pushad
mov edi,edx ; set EDI to buffer offset
mov dword [ebp - 4],ecx ; save buffer size
call ReadKeys
mov dword [ebp - 8], eax
cmp eax,0
jz .L5 ; skip move if zero chars input
cld ; search forward
mov ecx, dword [ebp - 4] ; repetition count for SCASB
dec ecx
mov al,NL ; scan for 0Ah (Line Feed) terminal character
repne scasb
jne .L1 ; if not found, jump to L1
;if we reach this line, length of input string <= (bufsize - 2)
dec dword [ebp - 8] ; second adjustment to bytesRead
dec edi ; 0Ah found: back up two positions
cmp edi,edx ; don't back up to before the user's buffer
jae .L2
mov edi,edx ; 0Ah must be the only byte in the buffer
jmp .L2 ; and jump to L2
.L1: mov edi,edx ; point to last byte in buffer
add edi,dword [ebp - 4]
dec edi
mov byte [edi],0 ; insert null byte
; Clear excess characters from the buffer, 1 byte at a time
.L6: call BufferFlush
jmp .L5
.L2: mov byte [edi],0 ; insert null byte
.L5: popad
mov eax, dword [ebp - 8]
leave
ret
;--------------- End of ReadString --------------------