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Correct typos in listing 3.1

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rnndxb wxcy 2016-03-03 13:07:27 -05:00
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src/chapter-03.md
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@ -163,34 +163,34 @@ presented in Chapter K on the companion CD-ROM.
; in when ZTimerOn was called. ; in when ZTimerOn was called.
; ;
Code segment word public ‘CODE' Code segment word public 'CODE'
assumecs: Code, ds:nothing assume cs:Code, ds:nothing
public ZTimerOn, ZTimerOff, ZTimerReport public ZTimerOn, ZTimerOff, ZTimerReport
; ;
; Base address of the 8253 timer chip. ; Base address of the 8253 timer chip.
; ;
BASE_8253equ40h BASE_8253 equ 40h
; ;
; The address of the timer 0 count registers in the 8253. ; The address of the timer 0 count registers in the 8253.
; ;
TIMER_0_8253 equBASE_8253 + 0 TIMER_0_8253 equ BASE_8253 + 0
; ;
; The address of the mode register in the 8253. ; The address of the mode register in the 8253.
; ;
MODE_8253 equBASE_8253 + 3 MODE_8253 equ BASE_8253 + 3
; ;
; The address of Operation Command Word 3 in the 8259 Programmable ; The address of Operation Command Word 3 in the 8259 Programmable
; Interrupt Controller (PIC) (write only, and writable only when ; 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). ; bit 4 of the byte written to this address is 0 and bit 3 is 1).
; ;
OCW3 equ20h OCW3 equ 20h
; ;
; The address of the Interrupt Request register in the 8259 PIC ; 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 ; (read only, and readable only when bit 1 of OCW3 = 1 and bit 0
; of OCW3 = 0). ; of OCW3 = 0).
; ;
IRR equ20h IRR equ 20h
; ;
; Macro to emulate a POPF instruction in order to fix the bug in some ; 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 ; 80286 chips which allows interrupts to occur during a POPF even when
@ -220,7 +220,7 @@ OriginalFlags db ? ; storage for upper byte of
; ZTimerOn called ; ZTimerOn called
TimedCount dw ? ; timer 0 count when the timer TimedCount dw ? ; timer 0 count when the timer
; is stopped ; is stopped
ReferenceCount dw ; number of counts required to ReferenceCount dw ? ; number of counts required to
; execute timer overhead code ; execute timer overhead code
OverflowFlag db ? ; used to indicate whether the OverflowFlag db ? ; used to indicate whether the
; timer overflowed during the ; timer overflowed during the
@ -229,28 +229,28 @@ OverflowFlag db ? ; used to indicate whether the
; String printed to report results. ; String printed to report results.
; ;
OutputStr label byte OutputStr label byte
db 0dh, 0ah, ‘Timed count: ‘, 5 dup (?) db 0dh, 0ah, 'Timed count: ', 5 dup (?)
ASCIICountEnd labelbyte ASCIICountEnd label byte
db ‘ microseconds', 0dh, 0ah db ' microseconds', 0dh, 0ah
db ‘$' db '$'
; ;
; String printed to report timer overflow. ; String printed to report timer overflow.
; ;
OverflowStr label byte OverflowStr label byte
db 0dh, 0ah db 0dh, 0ah
db ‘****************************************************' db '****************************************************'
db 0dh, 0ah db 0dh, 0ah
db ‘* The timer overflowed, so the interval timed was *' db '* The timer overflowed, so the interval timed was *'
db 0dh, 0ah db 0dh, 0ah
db ‘* too long for the precision timer to measure. *' db '* too long for the precision timer to measure. *'
db 0dh, 0ah db 0dh, 0ah
db ‘* Please perform the timing test again with the *' db '* Please perform the timing test again with the *'
db0dh, 0ah
db ‘* long-period timer. *'
db 0dh, 0ah db 0dh, 0ah
db ‘****************************************************' db '* long-period timer. *'
db 0dh, 0ah db 0dh, 0ah
db ‘$' db '****************************************************'
db 0dh, 0ah
db '$'
; ******************************************************************** ; ********************************************************************
; * Routine called to start timing. * ; * Routine called to start timing. *
@ -418,7 +418,7 @@ ZTimerOff endp
; Called by ZTimerOff to start timer for overhead measurements. ; Called by ZTimerOff to start timer for overhead measurements.
; ;
ReferenceZTimerOnproc near ReferenceZTimerOn proc near
; ;
; Save the context of the program being timed. ; Save the context of the program being timed.
; ;
@ -445,7 +445,7 @@ ReferenceZTimerOnproc near
pop ax pop ax
ret ret
ReferenceZTimerOnendp ReferenceZTimerOn endp
; ;
; Called by ZTimerOff to stop timer and add result to ReferenceCount ; Called by ZTimerOff to stop timer and add result to ReferenceCount
@ -488,7 +488,7 @@ ReferenceZTimerOff endp
; * Routine called to report timing results. * ; * Routine called to report timing results. *
; ******************************************************************** ; ********************************************************************
ZTimerReport procnear ZTimerReport proc near
pushf pushf
push ax push ax
@ -541,7 +541,7 @@ CTSLoop:
; ;
mov ah, 9 mov ah, 9
mov dx, offset OutputStr mov dx, offset OutputStr
int 21h int 21h
; ;
EndZTimerReport: EndZTimerReport:
pop ds pop ds
@ -2190,7 +2190,7 @@ call near ptr ReferenceZTimerOn
(and likewise for `ReferenceZTimerOff`), which works because (and likewise for `ReferenceZTimerOff`), which works because
`ReferenceZTimerOn` is in the same segment as the calling code. This `ReferenceZTimerOn` is in the same segment as the calling code. This
is normally a great optimization, being both smaller and faster than a is normally a great optimization, being both smaller and faster than a
far call. far call.
![**Figure 3.3**  *Changes for use with large code model C.*](images/03-03.jpg) ![**Figure 3.3**  *Changes for use with large code model C.*](images/03-03.jpg)