CP/M 2.2 - Revision history

Arnoldemu: /* Console Output */

2019-12-15T12:05:14Z

‎Console Output

Arnoldemu: /* Console Output */

2019-12-15T12:03:33Z

‎Console Output

Arnoldemu: /* Extra memory */

2019-12-08T11:46:24Z

‎Extra memory

Arnoldemu: /* MOVCPM */

2019-12-08T11:45:26Z

‎MOVCPM

Arnoldemu: /* Deleting a file that doesn't exist */

2019-12-08T11:44:41Z

‎Deleting a file that doesn't exist

Arnoldemu: /* Deleting a file that doesn't exist */

2019-12-08T11:43:46Z

‎Deleting a file that doesn't exist

Arnoldemu: /* Implementations */

2019-12-08T11:43:32Z

‎Implementations

Arnoldemu: /* Input */

2019-12-02T15:19:52Z

‎Input

Arnoldemu: /* Amstrad's implementation of CPM 2.2 */

2019-12-02T15:19:38Z

‎Amstrad's implementation of CPM 2.2

Arnoldemu: /* Amstrad's implementation of CPM 2.2 */

2019-07-07T11:01:18Z

‎Amstrad's implementation of CPM 2.2

@@ Line 83: / Line 83: @@
 ==== Console Output ====
-Console output (via BDOS functions) uses TXT OUTPUT so executes firmware control codes and displays CPC firmware characters.
+Console output (via BDOS functions) ultimately uses TXT OUTPUT so has the potential to execute firmware control codes and display CPC firmware characters.
-However, BDOS function 2 (Console output) looks for some specific characters and will perform specific processing regardless of whether it is part of a control character sequence or not.
+However, BDOS function 2 (Console output), which has control before TXT OUTPUT, looks for some specific characters and will perform specific processing regardless of whether it is part of a control character sequence or not.
-One of these is TAB (&09).
+Fore example, Console Output looks for TAB (&09).
-Therefore use BDOS function 6 (Direct console input/output) to avoid this processing. Therefore you can use the control codes to define windows, change modes, change colours etc.
+Therefore use BDOS function 6 (Direct console input/output) to avoid this processing. With this function you can use the control codes to define windows, change modes, change colours etc.
 ==== Serial number ====

@@ Line 83: / Line 83: @@
 ==== Console Output ====
-Console output (via BDOS functions) uses TXT OUTPUT so executes firmware control codes and displays CPC firmware characters. Therefore you can use the control codes to define windows, change modes, change colours etc.
+Console output (via BDOS functions) uses TXT OUTPUT so executes firmware control codes and displays CPC firmware characters.
 ==== Serial number ====

@@ Line 74: / Line 74: @@
 CPM2.2 doesn't use any extra memory, and since it runs in configuration 'C0' accessing extra memory is much quicker and easier than under CPM3.0.
 You should ensure your code (within the TPA) is in a safe region (0000-3fff, 8000-ffff), you can then page in the memory and copy it out to your destination directly as long as the destination is also within the safe area. It is much safer and simpler to use.
 ==== Console Input ====

@@ Line 108: / Line 108: @@
 otherwise you're using the stack set for CCP.
-==== MOVCPM ====
+==== MOVCPM.COM ====
-MOVCPM is used to change the size of the TPA which is the area used by programs. This relocates CCP and BDOS. SYSGEN then writes this to a disc so that when this disc is booted CP/M has a different sized TPA. By reducing the TPA, memory is freed up which is not touched by CPM and which can be used by the user.
+MOVCPM.COM is used to change the size of the TPA which is the area used by programs. This relocates CCP and BDOS. SYSGEN then writes this to a disc so that when this disc is booted CP/M has a different sized TPA. By reducing the TPA, memory is freed up which is not touched by CPM and which can be used by the user.
 CPM 2.2 is generated using MOVCPM on the CPM 2.2 disc as follows:

@@ Line 13: / Line 13: @@
 First check if a file exists before deleting it:
-   ld c,&11
+   ld c,&11            ;; search for first
    ld de,fcb
    call BDOS
@@ Line 19: / Line 19: @@
    jr z,doesnt_exist
-   ld c,&13
+   ld c,&13           ;; delete file
    ld de,fcb
    call BDOS

← Older revision		Revision as of 11:43, 8 December 2019
Line 4:		Line 4:

	CP/M 2.2 was the first CP/M avaiable for the Amstrad CPC. A minimum requirement to run CP/M was a disc drive therefore CP/M 2.2 came bundled with the Amstrad [[DDI-1]] discdrive with the BIOS in the AMSDOS ROM, making it possible to run CP/M 2.2 on the Amstrad CPC 464. Later when the Amstrad CPC 664 was released, CP/M 2.2 came together with this machine as the 664 had a built in discdrive. With the CPC6128 it was on one of the two system discs, with CPM+ on the other.		CP/M 2.2 was the first CP/M avaiable for the Amstrad CPC. A minimum requirement to run CP/M was a disc drive therefore CP/M 2.2 came bundled with the Amstrad [[DDI-1]] discdrive with the BIOS in the AMSDOS ROM, making it possible to run CP/M 2.2 on the Amstrad CPC 464. Later when the Amstrad CPC 664 was released, CP/M 2.2 came together with this machine as the 664 had a built in discdrive. With the CPC6128 it was on one of the two system discs, with CPM+ on the other.
		+
		+	== Tips ==
		+
		+	CPM 2.2 doesn't allow a program to handle BDOS errors itself like CPM+ does therefore you need to take additional steps to avoid them if you wish your program to continue:
		+
		+	=== Deleting a file that doesn't exist ===
		+
		+	First check if a file exists before deleting it:
		+
		+	ld c,&11
		+	ld de,fcb
		+	call BDOS
		+	cp 255
		+	jr z,doesnt_exist
		+
		+	ld c,&13
		+	ld de,fcb
		+	call BDOS
		+	doesnt_exist:
		+
		+	=== Disc change ===
		+
		+	If the disc is changed, e.g. another disc is inserted into drive A in a single disc system, then the disc will be marked as read-only. Any modification operations (e.g. delete or write) will fail and the program will be aborted with a BDOS read-only error.
		+
		+	To avoid this reset the disk system and re-select the current drive:
		+
		+	ld c,&19 ;; get current disk
		+	call BDOS
		+	push af
		+	ld c,&0d ;; reset disk system
		+	call BDOS
		+	pop af
		+	ld e,a
		+	ld c,&0e ;; select disk restoring it to read/write state
		+	call BDOS

	== Implementations ==		== Implementations ==

@@ Line 40: / Line 40: @@
 You should ensure your code (within the TPA) is in a safe region (0000-3fff, 8000-ffff), you can then page in the memory and copy it out to your destination directly as long as the destination is also within the safe area. It is much safer and simpler to use.
-==== Input ====
+==== Console Input ====
 Console input (via BDOS functions) uses firmware functions and returns firmware key codes when a key is pressed. i.e. &f0 is cursor up.

← Older revision		Revision as of 11:01, 7 July 2019
Line 34:		Line 34:

	You can then add additional files using FILECOPY.		You can then add additional files using FILECOPY.
		+
		+	==== Extra memory ====
		+
		+	CPM2.2 doesn't use any extra memory, and since it runs in configuration 'C0' accessing extra memory is much quicker and easier than under CPM3.0.
		+	You should ensure your code (within the TPA) is in a safe region (0000-3fff, 8000-ffff), you can then page in the memory and copy it out to your destination directly as long as the destination is also within the safe area. It is much safer and simpler to use.

	==== Serial number ====		==== Serial number ====