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问题描述
我在此处提出了类似的问题，但我更换了汇编器，这个问题几乎完全改变了，因此为了避免问题混乱，我发布了一个全新的问题.总之，长话短说，我正在Windows 7上，并且刚刚安装了NASM，并且我正试图从Michael Abrash撰写的一本名为《汇编的禅》的书中汇编代码清单.这是清单的代码:
I asked a similar question here but I changed assemblers and the question almost entirely changed, so in an effort to avoid question clutter I'm posting an entirely new question. Anyways, long story short, I'm on Windows 7 and I just installed NASM, and I'm trying to assemble a code listing from a book called Zen of Assembly by Michael Abrash. Here's the code for the listing:
;
; *** Listing 2-1 ***
;
; The precision Zen timer (PZTIMER.ASM)
;
; Uses the 8253 timer to time the performance of code that takes
; less than about 54 milliseconds to execute, with a resolution
; of better than 10 microseconds.
;
; By Michael Abrash 4/26/89
;
; Externally callable routines:
;
; ZTimerOn: Starts the Zen timer, with interrupts disabled.
;
; ZTimerOff: Stops the Zen timer, saves the timer count,
; times the overhead code, and restores interrupts to the
; state they were in when ZTimerOn was called.
;
; ZTimerReport: Prints the net time that passed between starting
; and stopping the timer.
;
; Note: If longer than about 54 ms passes between ZTimerOn and
; ZTimerOff calls, the timer turns over and the count is
; inaccurate. When this happens, an error message is displayed
; instead of a count. The long-period Zen timer should be used
; in such cases.
;
; Note: Interrupts *MUST* be left off between calls to ZTimerOn
; and ZTimerOff for accurate timing and for detection of
; timer overflow.
;
; Note: These routines can introduce slight inaccuracies into the
; system clock count for each code section timed even if
; timer 0 doesn't overflow. If timer 0 does overflow, the
; system clock can become slow by virtually any amount of
; time, since the system clock can't advance while the
; precison timer is timing. Consequently, it's a good idea
; to reboot at the end of each timing session. (The
; battery-backed clock, if any, is not affected by the Zen
; timer.)
;
; All registers, and all flags except the interrupt flag, are
; preserved by all routines. Interrupts are enabled and then disabled
; by ZTimerOn, and are restored by ZTimerOff to the state they were
; in when ZTimerOn was called.
;
Code segment word public 'CODE'
assume cs:Code, ds:nothing
public ZTimerOn, ZTimerOff, ZTimerReport
;
; Base address of the 8253 timer chip.
;
BASE_8253 equ 40h
;
; The address of the timer 0 count registers in the 8253.
;
TIMER_0_8253 equ BASE_8253 + 0
;
; The address of the mode register in the 8253.
;
MODE_8253 equ BASE_8253 + 3
;
; The address of Operation Command Word 3 in the 8259 Programmable
; Interrupt Controller (PIC) (write only, and writable only when
; bit 4 of the byte written to this address is 0 and bit 3 is 1).
;
OCW3 equ 20h
;
; The address of the Interrupt Request register in the 8259 PIC
; (read only, and readable only when bit 1 of OCW3 = 1 and bit 0
; of OCW3 = 0).
;
IRR equ 20h
;
; Macro to emulate a POPF instruction in order to fix the bug in some
; 80286 chips which allows interrupts to occur during a POPF even when
; interrupts remain disabled.
;
MPOPF macro
local p1, p2
jmp short p2
p1: iret ;jump to pushed address & pop flags
p2: push cs ;construct far return address to
call p1 ; the next instruction
endm
;
; Macro to delay briefly to ensure that enough time has elapsed
; between successive I/O accesses so that the device being accessed
; can respond to both accesses even on a very fast PC.
;
DELAY macro
jmp $+2
jmp $+2
jmp $+2
endm
OriginalFlags db ? ;storage for upper byte of
; FLAGS register when
; ZTimerOn called
TimedCount dw ? ;timer 0 count when the timer
; is stopped
ReferenceCount dw ? ;number of counts required to
; execute timer overhead code
OverflowFlag db ? ;used to indicate whether the
; timer overflowed during the
; timing interval
;
; String printed to report results.
;
OutputStr label byte
db 0dh, 0ah, 'Timed count: ', 5 dup (?)
ASCIICountEnd label byte
db ' microseconds', 0dh, 0ah
db '$'
;
; String printed to report timer overflow.
;
OverflowStr label byte
db 0dh, 0ah
db '****************************************************'
db 0dh, 0ah
db '* The timer overflowed, so the interval timed was *'
db 0dh, 0ah
db '* too long for the precision timer to measure. *'
db 0dh, 0ah
db '* Please perform the timing test again with the *'
db 0dh, 0ah
db '* long-period timer. *'
db 0dh, 0ah
db '****************************************************'
db 0dh, 0ah
db '$'
;********************************************************************
;* Routine called to start timing. *
;********************************************************************
ZTimerOn proc near
;
; Save the context of the program being timed.
;
push ax
pushf
pop ax ;get flags so we can keep
; interrupts off when leaving
; this routine
mov cs:[OriginalFlags],ah ;remember the state of the
; Interrupt flag
and ah,0fdh ;set pushed interrupt flag
; to 0
push ax
;
; Turn on interrupts, so the timer interrupt can occur if it's
; pending.
;
sti
;
; Set timer 0 of the 8253 to mode 2 (divide-by-N), to cause
; linear counting rather than count-by-two counting. Also
; leaves the 8253 waiting for the initial timer 0 count to
; be loaded.
;
mov al,00110100b ;mode 2
out MODE_8253,al
;
; Set the timer count to 0, so we know we won't get another
; timer interrupt right away.
; Note: this introduces an inaccuracy of up to 54 ms in the system
; clock count each time it is executed.
;
DELAY
sub al,al
out TIMER_0_8253,al ;lsb
DELAY
out TIMER_0_8253,al ;msb
;
; Wait before clearing interrupts to allow the interrupt generated
; when switching from mode 3 to mode 2 to be recognized. The delay
; must be at least 210 ns long to allow time for that interrupt to
; occur. Here, 10 jumps are used for the delay to ensure that the
; delay time will be more than long enough even on a very fast PC.
;
rept 10
jmp $+2
endm
;
; Disable interrupts to get an accurate count.
;
cli
;
; Set the timer count to 0 again to start the timing interval.
;
mov al,00110100b ;set up to load initial
out MODE_8253,al ; timer count
DELAY
sub al,al
out TIMER_0_8253,al ;load count lsb
DELAY
out TIMER_0_8253,al ;load count msb
;
; Restore the context and return.
;
MPOPF ;keeps interrupts off
pop ax
ret
ZTimerOn endp
;********************************************************************
;* Routine called to stop timing and get count. *
;********************************************************************
ZTimerOff proc near
;
; Save the context of the program being timed.
;
push ax
push cx
pushf
;
; Latch the count.
;
mov al,00000000b ;latch timer 0
out MODE_8253,al
;
; See if the timer has overflowed by checking the 8259 for a pending
; timer interrupt.
;
mov al,00001010b ;OCW3, set up to read
out OCW3,al ; Interrupt Request register
DELAY
in al,IRR ;read Interrupt Request
; register
and al,1 ;set AL to 1 if IRQ0 (the
; timer interrupt) is pending
mov cs:[OverflowFlag],al ;store the timer overflow
; status
;
; Allow interrupts to happen again.
;
sti
;
; Read out the count we latched earlier.
;
in al,TIMER_0_8253 ;least significant byte
DELAY
mov ah,al
in al,TIMER_0_8253 ;most significant byte
xchg ah,al
neg ax ;convert from countdown
; remaining to elapsed
; count
mov cs:[TimedCount],ax
; Time a zero-length code fragment, to get a reference for how
; much overhead this routine has. Time it 16 times and average it,
; for accuracy, rounding the result.
;
mov cs:[ReferenceCount],0
mov cx,16
cli ;interrupts off to allow a
; precise reference count
RefLoop:
call ReferenceZTimerOn
call ReferenceZTimerOff
loop RefLoop
sti
add cs:[ReferenceCount],8 ;total + (0.5 * 16)
mov cl,4
shr cs:[ReferenceCount],cl ;(total) / 16 + 0.5
;
; Restore original interrupt state.
;
pop ax ;retrieve flags when called
mov ch,cs:[OriginalFlags] ;get back the original upper
; byte of the FLAGS register
and ch,not 0fdh ;only care about original
; interrupt flag...
and ah,0fdh ;...keep all other flags in
; their current condition
or ah,ch ;make flags word with original
; interrupt flag
push ax ;prepare flags to be popped
;
; Restore the context of the program being timed and return to it.
;
MPOPF ;restore the flags with the
; original interrupt state
pop cx
pop ax
ret
ZTimerOff endp
;
; Called by ZTimerOff to start timer for overhead measurements.
;
ReferenceZTimerOn proc near
;
; Save the context of the program being timed.
;
push ax
pushf ;interrupts are already off
;
; Set timer 0 of the 8253 to mode 2 (divide-by-N), to cause
; linear counting rather than count-by-two counting.
;
mov al,00110100b ;set up to load
out MODE_8253,al ; initial timer count
DELAY
;
; Set the timer count to 0.
;
sub al,al
out TIMER_0_8253,al ;load count lsb
DELAY
out TIMER_0_8253,al ;load count msb
;
; Restore the context of the program being timed and return to it.
;
MPOPF
pop ax
ret
ReferenceZTimerOn endp
;
; Called by ZTimerOff to stop timer and add result to ReferenceCount
; for overhead measurements.
;
ReferenceZTimerOff proc near
;
; Save the context of the program being timed.
;
push ax
push cx
pushf
;
; Latch the count and read it.
;
mov al,00000000b ;latch timer 0
out MODE_8253,al
DELAY
in al,TIMER_0_8253 ;lsb
DELAY
mov ah,al
in al,TIMER_0_8253 ;msb
xchg ah,al
neg ax ;convert from countdown
; remaining to amount
; counted down
add cs:[ReferenceCount],ax
;
; Restore the context of the program being timed and return to it.
;
MPOPF
pop cx
pop ax
ret
ReferenceZTimerOff endp
;********************************************************************
;* Routine called to report timing results. *
;********************************************************************
ZTimerReport proc near
pushf
push ax
push bx
push cx
push dx
push si
push ds
;
push cs ;DOS functions require that DS point
pop ds ; to text to be displayed on the screen
assume ds:Code
;
; Check for timer 0 overflow.
;
cmp [OverflowFlag],0
jz PrintGoodCount
mov dx,offset OverflowStr
mov ah,9
int 21h
jmp short EndZTimerReport
;
; Convert net count to decimal ASCII in microseconds.
;
PrintGoodCount:
mov ax,[TimedCount]
sub ax,[ReferenceCount]
mov si,offset ASCIICountEnd - 1
;
; Convert count to microseconds by multiplying by .8381.
;
mov dx,8381
mul dx
mov bx,10000
div bx ;* .8381 = * 8381 / 10000
;
; Convert time in microseconds to 5 decimal ASCII digits.
;
mov bx,10
mov cx,5
CTSLoop:
sub dx,dx
div bx
add dl,'0'
mov [si],dl
dec si
loop CTSLoop
;
; Print the results.
;
mov ah,9
mov dx,offset OutputStr
int 21h
;
EndZTimerReport:
pop ds
pop si
pop dx
pop cx
pop bx
pop ax
MPOPF
ret
ZTimerReport endp
Code ends
end
我将nasm.exe添加到了我的路径，将该文件另存为listing1.asm，并尝试使用以下CMD命令进行组装:
I added nasm.exe to my path, saved this file as listing1.asm, and tried to use the following CMD command to assemble it:
nasm -f win32 listing1.asm
但是，它没有组装，而是给了我以下错误:
However, it didn't assemble, and instead gave me the following errors:
listing1.asm:50: error: parser: instruction expected
listing1.asm:51: error: parser: instruction expected
listing1.asm:82: error: parser: instruction expected
listing1.asm:83: error: parser: instruction expected
listing1.asm:95: error: parser: instruction expected
listing1.asm:99: error: symbol `endm' redefined
listing1.asm:114: error: parser: instruction expected
listing1.asm:115: error: comma expected after operand 4
listing1.asm:116: error: parser: instruction expected
listing1.asm:122: error: parser: instruction expected
listing1.asm:142: error: parser: instruction expected
listing1.asm:176: error: symbol `DELAY' redefined
listing1.asm:179: error: symbol `DELAY' redefined
listing1.asm:188: error: parser: instruction expected
listing1.asm:190: error: symbol `endm' redefined
listing1.asm:200: error: symbol `DELAY' redefined
listing1.asm:203: error: symbol `DELAY' redefined
listing1.asm:208: error: symbol `MPOPF' redefined
listing1.asm:212: error: symbol `ZTimerOn' redefined
listing1.asm:212: error: parser: instruction expected
listing1.asm:218: error: parser: instruction expected
listing1.asm:237: error: symbol `DELAY' redefined
listing1.asm:252: error: symbol `DELAY' redefined
listing1.asm:282: error: comma, colon or end of line expected
listing1.asm:292: error: symbol `MPOPF' redefined
listing1.asm:298: error: symbol `ZTimerOff' redefined
listing1.asm:298: error: parser: instruction expected
listing1.asm:304: error: parser: instruction expected
listing1.asm:316: error: symbol `DELAY' redefined
listing1.asm:322: error: symbol `DELAY' redefined
listing1.asm:327: error: symbol `MPOPF' redefined
listing1.asm:331: error: symbol `ReferenceZTimerOn' redefined
listing1.asm:331: error: parser: instruction expected
listing1.asm:338: error: parser: instruction expected
listing1.asm:350: error: symbol `DELAY' redefined
listing1.asm:352: error: symbol `DELAY' redefined
listing1.asm:363: error: symbol `MPOPF' redefined
listing1.asm:368: error: symbol `ReferenceZTimerOff' redefined
listing1.asm:368: error: parser: instruction expected
listing1.asm:374: error: parser: instruction expected
listing1.asm:386: error: symbol `assume' redefined
listing1.asm:386: error: parser: instruction expected
listing1.asm:392: error: comma, colon or end of line expected
listing1.asm:402: error: comma, colon or end of line expected
listing1.asm:426: error: comma, colon or end of line expected
listing1.asm:436: error: symbol `MPOPF' redefined
listing1.asm:439: error: symbol `ZTimerReport' redefined
listing1.asm:439: error: parser: instruction expected
listing1.asm:441: error: symbol `Code' redefined
listing1.asm:441: error: parser: instruction expected
不确定我应该在这里做什么；我尝试了一下Google搜索，但没有提出任何建议.有人认识到这些错误吗?
Not sure what I should do here; I've tried googling around a little bit but haven't come up with anything. Anyone recognize these errors?
推荐答案
该汇编语言是MASM，而不是NASM.
That assembly language is MASM, not NASM.
对于初学者，NASM段的定义不同.
For starters, NASM segments are defined differently.
代替
Code segment word public 'CODE'
我们写
.section text
还有"ASSUME"声明……您必须有一本古老的书.那是旧的，古老的MASM代码.带给我1980年代初期的回忆！
And that "ASSUME" declaration... You must have an ancient book. That is old, old MASM code. Brings back memories from the early 1980s for me!
NASM和MASM之间有许多区别，并且您的代码需要大量工作才能移植.如果要将该MASM代码移植到NASM，请参见 MASM/NASM差异或NASM文档或Google "NASM与MASM"
There are many differences between NASM and MASM, and your code needs quite a bit of work to port. If you want to port that MASM code to NASM, see MASM/NASM Differences or the NASM documentation or google "NASM vs MASM"
TL; DR:您正在编写MASM代码，而不是NASM.
TL;DR: you are writing MASM code, not NASM.
这篇关于NASM错误解析，预期指令的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！