int 21h/0Ah service: what are those "templates"?

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DimonSoft

Joined: 03 Mar 2010
Posts: 1228
Location: Belarus

DimonSoft 17 Mar 2014, 11:12

I've used the function for a long time but recently I've noticed that there's additional information in TechHelp. Here's the link: DOS Fn 0aH: Buffered String Input (see "Notes" section). The F3 and F5 keys really work as documented but I couldn't find a way to make the function use the initial buffer contents as a "template".

Could anyone, please, give more information on what these templates are and what values should be put to the input buffer in order to make the use of "templates"?

17 Mar 2014, 11:12

baldr

Joined: 19 Mar 2008
Posts: 1651

baldr 17 Mar 2014, 11:56

DimonSoft,

I've made some tests and it seems that template should have trailing CR (not accounted by the len field as specified). Quick look at $Std_Con_Input_String in MS-DOS 6.0 sources reveals that it indeed expects CR there.

17 Mar 2014, 11:56

DimonSoft

Joined: 03 Mar 2010
Posts: 1228
Location: Belarus

DimonSoft 17 Mar 2014, 13:51

baldr wrote:

DimonSoft,

I've made some tests and it seems that template should have trailing CR (not accounted by the len field as specified). Quick look at $Std_Con_Input_String in MS-DOS 6.0 sources reveals that it indeed expects CR there.

Could you, please, give more information? First of all, what does this template actually do and how can a user make the use of it? Pressing F3 doesn't seem to work. Maybe I'm initializing the buffer the wrong way.

17 Mar 2014, 13:51

baldr

Joined: 19 Mar 2008
Posts: 1651

baldr 17 Mar 2014, 18:46

DimonSoft,

Examine the following debug session:

Code:

-a 100
1418:0100 mov   ah, 0A
1418:0102 mov   dx, 200
1418:0105 int   21
1418:0107 ret
1418:0108
-e 200 20 0D "Hello, world!" 0D
-g 107
Hello, world!@
Goodbye, world!
AX=0A0D  BX=0000  CX=0000  DX=0200  SP=FFEE  BP=0000  SI=0000  DI=0000
DS=1418  ES=1418  SS=1418  CS=1418  IP=0107   NV UP EI PL NZ NA PO NC
1418:0107 C3            RET
-d 200 221
1418:0200  20 0F 47 6F 6F 64 62 79-65 2C 20 77 6F 72 6C 64    .Goodbye, world
1418:0210  21 0D 00 00 00 00 00 00-00 00 00 00 00 00 00 00   !...............
1418:0220  00 00                                             ..
-

In e 200… command the first 0D is the len field contents (number of characters in "Hello, world!" text), second one is the trailing CR.

After g 107 command I've pressed F3 then F5 to show template buffer and start over; then I've typed "Goodb" which will replace "Hello", switched to insert mode with Ins, typed "ye" and pressed F3 again to append the rest of the template (namely ", world!"); Enter finished the input.

17 Mar 2014, 18:46

DimonSoft

Joined: 03 Mar 2010
Posts: 1228
Location: Belarus

DimonSoft 18 Mar 2014, 07:42

baldr wrote:

DimonSoft,

Examine the following debug session:
Code:
-a 100
1418:0100 mov   ah, 0A
1418:0102 mov   dx, 200
1418:0105 int   21
1418:0107 ret
1418:0108
-e 200 20 0D "Hello, world!" 0D
-g 107
Hello, world!@
Goodbye, world!
AX=0A0D  BX=0000  CX=0000  DX=0200  SP=FFEE  BP=0000  SI=0000  DI=0000
DS=1418  ES=1418  SS=1418  CS=1418  IP=0107   NV UP EI PL NZ NA PO NC
1418:0107 C3            RET
-d 200 221
1418:0200  20 0F 47 6F 6F 64 62 79-65 2C 20 77 6F 72 6C 64    .Goodbye, world
1418:0210  21 0D 00 00 00 00 00 00-00 00 00 00 00 00 00 00   !...............
1418:0220  00 00                                             ..
-    
In e 200… command the first 0D is the len field contents (number of characters in "Hello, world!" text), second one is the trailing CR.

After g 107 command I've pressed F3 then F5 to show template buffer and start over; then I've typed "Goodb" which will replace "Hello", switched to insert mode with Ins, typed "ye" and pressed F3 again to append the rest of the template (namely ", world!"); Enter finished the input.

Thanks, that's a great example. Everything works fine and now I have more information to tell my students. Thanks again.

18 Mar 2014, 07:42

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