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Q73746: DOCERR: MASM 6.0 Programmer's Guide Errors: Chapter 7 |
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Article: Q73746
Product(s): Microsoft Macro Assembler
Version(s): MS-DOS:6.0,6.0a,6.0b
Operating System(s):
Keyword(s):
Last Modified: 06-MAY-2001
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The information in this article applies to:
- Microsoft Macro Assembler (MASM), versions 6.0, 6.0a, 6.0b
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SUMMARY
=======
The following is a list of documentation additions and corrections for chapter 7
of the "Microsoft Macro Assembler Programmer's Guide" version 6.0 manual. The
section and page numbers are listed first, followed by a description of the
addition or correction.
Section 7.1, Page 167
---------------------
The first paragraph of this section should read:
Jumps are the most direct method for changing program control from one
location to another. At the processor level, jumps work by changing the value
of the IP (Instruction Pointer) for near jumps, and by changing the values of
the CS and IP registers for far jumps. The IP register is loaded with the
offset of the target address and CS is loaded with the segment of the target
address. The many forms of the jump instruction handle jumps based on
conditions, flags, and bit settings.
Section 7.1.1.2, Page 169
-------------------------
The sample line
jmp ebx ; FAR32 jump
should read:
jmp ebx ; NEAR32 jump
In addition, replace FAR32 with NEAR32 in the sentence before the above line.
Section 7.1.1.2, Page 170
-------------------------
The example shows the following TYPEDEF statement:
NPVOID TYPEDEF NEAR PTR VOID
Note that VOID is not a defined type. It acts as a placeholder and improves
program readability. In this case, the TYPEDEF is equivalent to:
NPVOID TYPEDEF NEAR PTR
Section 7.1.2.2, Page 173
-------------------------
Table 7.1, on page 173, uses the same character for the number zero and the
letter "O." This may cause some confusion when reading the table. The "OF"
indicates the overflow flag and does not represent the hexadecimal number 0F.
Section 7.1.2.6, Page 176
-------------------------
In the sample code, the line
.IF cx = 20
should be:
.IF cx == 20
Section 7.2, Page 177
---------------------
The description of the LOOPE, LOOPZ, LOOPNE, and LOOPNZ states:
Loops while equal (or not equal). Checks CX and a condition. The loop ends
when the condition is true. Set CX to a number out of range if you don't want
to control the loop.
It should read:
Loops while equal (or not equal). Checks CX and a condition (indicated by the
zero flag). The loop continues while the condition is met and CX is not zero.
Set CX to a number out of range if you don't want the CX count to control the
loop.
Section 7.3.2, Page 187
-----------------------
The sample program contains a line that states:
mov sp, bp
Because there are no local variables and the SP register is not otherwise
modified, this line is not needed.
Section 7.3.3.2, Page 191
-------------------------
This first paragraph states:
The parameters are separated from the reglist by a comma if there is a list
of registers.
According to the BNF grammar shown in Appendix B, the above statement is
incorrect. The comma is optional and is required only if the parameters are
placed on the next line.
For example,
myproc PROC FAR C PUBLIC USES di si, var1:word, arg1:VARARG
is equivalent to:
myproc PROC FAR C PUBLIC USES di si var1:word, arg1:VARARG
Note in the last case there is no comma following the SI register.
Section 7.3.3.3, Page 193
-------------------------
The sample program contains the line:
dec arg1
It should read:
dec argcount
Section 7.3.6, Page 199
-----------------------
Page 199 shows two sample lines for declaring prototypes. They are:
addup PROTO NEAR C argcount:WORD, arg2:WORD, arg3:WORD
myproc PROTO FAR C, argcount:WORD, arg2:VARARG
The last prototype has a comma following the C language specifier while the first
prototype does not. The documentation fails to mention that the comma is
optional; therefore, both statements are correct.
Section 7.3.7.5, Page 202 and 203
---------------------------------
In the first example, the code is missing a few steps. The following is the
corrected code:
.CODE
mov bx, pfunc ; pfunc is the Function Table
mov si, Num ; Num contains 0 or 2
INVOKE FUNCPTR PTR [bx+si], 1, 1 ; Selects proc1 or proc2
The first paragraph on page 203 states:
You can also use ASSUME to accomplish the same task. The ASSUME statement
associates the type PFUNC with the BX register.
It should read:
You can also use ASSUME to accomplish the same task. In the sample below, the
ASSUME statement associates the type FUNCPTR with the BX register.
In the example that follows, add the following line after the ASSUME:
mov bx, pFunc
Change the INVOKE line to read:
INVOKE [bx+si], 1, 1
Section 7.3.8.2, Page 205
-------------------------
Page 205 shows the epilogue code when <LOADDS> is specified on a PROC line.
One line states:
mov sp,bp
It should read:
mov sp,bp ; if localbytes is not 0
Section 7.4.1, Page 209
-----------------------
The sample code demonstrates how to print a message on the display using a DOS
interrupt call. It shows the following code:
.DATA
msg BYTE "This writes to the screen",$
.CODE
mov dx,offset msg
mov ah,09h
int 21h
It should read:
.DATA
msg BYTE "This writes to the screen$"
.CODE
mov ax,SEG msg
mov ds,ax
mov dx,offset msg
mov ah,09h
int 21h
Section 7.4.2, Page 211
-----------------------
The last paragraph states:
To replace the address in the interrupt descriptor table with the address of
your procedure, AL needs to be loaded with 04h and AH loaded with 35, the Get
Interrupt Vector function. The Set Interrupt Vector function requires 25 in
AH.
The numbers 35 and 25 are presented in hexadecimal rather than decimal. They
should be written as 25h and 35h.
Section 7.4.2, Page 212
-----------------------
Change the line
.MODEL LARGE,C,DOS
to:
.MODEL LARGE,C,OS_DOS
Also, the last sentence on page 212 should read:
Before your program ends, you should restore the original address by loading
DS and DX with the original interrupt address and using the DOS set vector
function to store the original address at the correct location.
Additional query words: 6.00 6.00a 6.00b
======================================================================
Keywords :
Technology : kbMASMsearch kbAudDeveloper kbMASM600 kbMASM600a kbMASM600b
Version : MS-DOS:6.0,6.0a,6.0b
=============================================================================
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