Update our sample code (#224)

Removed a bunch of old examples that are not so useful, and tidied up the remaining ones:

* Removed unused bytes and labels.
* Updated to ensure that several reported upon the correct drive-letter.
* Little tweaks to make behaviour better.
   * e.g. Testing that creating a file worked, or ensuring a file exists before trying to delete it.

This closes #222.

Author: skx

samples/Makefile

@@ -3,9 +3,9 @@
 # The files we wish to generate.
 #
 all: cli-args.com create.com \
-     delete.com drive.com filesize.com find.com \
-     intest.com read.com ret.com terminal.com test.com \
-     unimpl.com user-num.com version.com write.com
+     delete.com filesize.com find.com \
+     intest.com read.com ret.com tsize.com \
+     write.com
 
 
 #

samples/README.md

@@ -21,6 +21,10 @@ More significant programs are available within the sister-repository:
   * Create a file, given the name.
 * [delete.z80](delete.z80)
   * Delete files matching the given name/pattern.
+* [filesize.z80](filesize.z80)
+  * Show the size of the given file.
+* [find.z80](find.z80)
+  * Find files via their names.
 * [intest.z80](intest.z80)
   * Test the various character/line input methods for correctness.
 * [read.z80](read.z80) & [write.z80](write.z80)
@@ -29,7 +33,5 @@ More significant programs are available within the sister-repository:
   * Used to test sequential read/write operations.
 * [ret.z80](ret.z80)
   * Terminate the execution of a binary in four different ways.
-* [terminal.z80](terminal.z80)
+* [tsize.z80](tsize.z80)
   * Show the dimensions of the terminal we're running within.
-* [unimpl.z80](unimpl.z80)
-  * Attempt to call a BDOS function which isn't implemented.

samples/cli-args.com

@@ -65,15 +65,29 @@ DUMP_FCB:
         PUSH HL
         LD A, (HL)
 
-        ; A should have the drive number 0 means A, 1 for B, etc
-        add a,'A'
+        ;; If the drive is not-zero that means we have an explicit drive
+        cp 0x00
+        jr nz, letter_drive
 
-        ; Show drive
+        ;; So the drive is 0x00, which means we're using the current,
+        ;; or default, drive.  Find it.
+        ld c,25
+        call 0x0005
+
+        ;; Add one, now we can fall-through to the ASCII conversiion
+        inc a
+
+letter_drive:
+        ; 1 means A, 2 for B, etc
+        add a,'A' -1
+
+show_drive:
+        ;; Show the drive letter
         LD     E,A
         LD     C,0x02
         CALL   0x0005
 
-        ; Show ":"
+        ;; And the ":"
         LD     E,':'
         LD     C,0x02
         CALL   0x0005

samples/cli-args.z80

@@ -1,12 +1,11 @@
 ;; create.asm - Create the named file
-;;
 
 FCB1:    EQU 0x5C
 
-BDOS_ENTRY_POINT:    EQU 5
-
-BDOS_OUTPUT_STRING:            EQU 9
-BDOS_MAKE_FILE:                EQU 22
+BDOS_ENTRY_POINT:    EQU  5
+BDOS_OUTPUT_STRING:  EQU  9
+BDOS_OPEN_FILE:      EQU 15
+BDOS_MAKE_FILE:      EQU 22
 
         ;;
         ;; CP/M programs start at 0x100.
@@ -29,24 +28,58 @@ BDOS_MAKE_FILE:                EQU 22
         jr     exit_fn
 
 got_argument:
-        LD DE, FCB1
-        LD C, 22
-        CALL BDOS_ENTRY_POINT
+        ;; First of all try to open the file
+        ;; if this succeeds it means the file
+        ;; exists, so we cannot create it, and we
+        ;; must terminate.
+        call can_open
+        jr z,   already_present
+
+        ;; Now try to create the file.
+        ld de, FCB1
+        ld c,  BDOS_MAKE_FILE
+        call   BDOS_ENTRY_POINT
+
+        ;; If we can no open it then we created the
+        ;; file, and all is good.
+        call can_open
+        jr nz, failed_create
 
 exit_fn:
         ;; exit
-        LD      C,0x00
-        CALL    BDOS_ENTRY_POINT
+        ld      c,0x00
+        call    BDOS_ENTRY_POINT
 
 
-;;;
-;;; The message displayed if no command-line argument was present.
-;;;
-usage_message:
-        db "Usage: CREATE FILENAME.EXT"
+;;  Test if we can open the file in the first FCB
+can_open:
+        ;; Open the file
+        ld de,  FCB1
+        ld c,   BDOS_OPEN_FILE
+        call    BDOS_ENTRY_POINT
+
+        ;; Did that succeed?
+        cp 00
+        ret
 
-        ;; note fall-through here :)
-newline:
-        db 0xa, 0xd, "$"
+already_present:
+        ld de, present_message
+        ld c,  BDOS_OUTPUT_STRING
+        call   BDOS_ENTRY_POINT
+        jr     exit_fn
+
+failed_create:
+        ld de, failed_message
+        ld c,  BDOS_OUTPUT_STRING
+        call   BDOS_ENTRY_POINT
+        jr     exit_fn
+
+;;; Message area
+failed_message:
+        DB "Failed to create the file.", 0x0a, 0x0d, "$"
+present_message:
+        DB "The file is already present, we cannot create it.", 0x0a, 0x0d, "$"
+usage_message:
+        db "Usage: CREATE FILENAME.EXT", 0xa, 0xd, "$"
 
 END

samples/create.com

@@ -5,8 +5,9 @@ FCB1:    EQU 0x5C
 
 BDOS_ENTRY_POINT:    EQU 5
 
-BDOS_OUTPUT_STRING:            EQU 9
-BDOS_DELETE_FILE:              EQU 19
+BDOS_OUTPUT_STRING:  EQU  9
+BDOS_OPEN_FILE:      EQU 15
+BDOS_DELETE_FILE:    EQU 19
 
         ;;
         ;; CP/M programs start at 0x100.
@@ -29,24 +30,56 @@ BDOS_DELETE_FILE:              EQU 19
         jr     exit_fn
 
 got_argument:
+        ;; Can we open the file?
+        ;; i.e. if it doesn't exist we must abort
+        call can_open
+        jr nz, not_found
+
+        ;; file exists, we can delete it.
         LD DE, FCB1
         LD C, BDOS_DELETE_FILE
         CALL BDOS_ENTRY_POINT
 
+        ;; did it work?
+        call can_open
+        jr z,   delete_failed
+
 exit_fn:
         ;; exit
         LD      C,0x00
         CALL    BDOS_ENTRY_POINT
 
+not_found:
+        ld de,  NOT_FOUND_MESSAGE
+        ld c,   BDOS_OUTPUT_STRING
+        call   BDOS_ENTRY_POINT
+        jr     exit_fn
+
+delete_failed:
+        ld de,  DELETE_FAILED_MESSAGE
+        ld c,   BDOS_OUTPUT_STRING
+        call   BDOS_ENTRY_POINT
+        jr     exit_fn
+
+;;  Test if we can open the file in the first FCB
+can_open:
+        ;; Open the file
+        ld de,  FCB1
+        ld c,   BDOS_OPEN_FILE
+        call    BDOS_ENTRY_POINT
+
+        ;; Did that succeed?
+        cp 00
+        ret
 
 ;;;
 ;;; The message displayed if no command-line argument was present.
 ;;;
+DELETE_FAILED_MESSAGE:
+        db "Deleting the file failed.", 0x0a, 0x0d, "$"
+NOT_FOUND_MESSAGE:
+        db "The file does does not exist.", 0x0a, 0x0d, "$"
 usage_message:
-        db "Usage: DELETE FILENAME.EXT"
-
-        ;; note fall-through here :)
-newline:
-        db 0xa, 0xd, "$"
+        db "Usage: DELETE FILENAME.EXT", 0xa, 0xd, "$"
 
 END

samples/create.z80

@@ -1,6 +1,4 @@
-;; find.asm
-;;
-;; Show all files which match the given glob/pattern.
+;; find.asm - Show all files which match the given glob/pattern.
 ;;
 
 FCB1:    EQU 0x5C
@@ -94,8 +92,22 @@ show_result:
 
         push af                 ; preserve return code from find first/next
 
-        ld a,(FCB1)             ; Output the drive-letter and separator
-        add a, 65 - 1
+        ;; If the drive is not-zero that means we have an explicit drive
+        ld a,(FCB1)
+        cp 0x00
+        jr nz, letter_drive
+
+        ;; So the drive is 0x00, which means we're using the current,
+        ;; or default, drive.  Find it.
+        ld c,25
+        call 0x0005
+
+        ;; Add one, now we can fall-through to the ASCII conversiion
+        inc a
+
+letter_drive:
+        ; 1 means A, 2 for B, etc
+        add a,'A' -1
         call print_character
 
         ld a, ':'
@@ -186,16 +198,9 @@ call_bdos_and_return:
 ;;; The message displayed if no command-line argument was present.
 ;;;
 usage_message:
-        db "Usage: LOCATE pattern"
-
+        db "Usage: FIND pattern"
         ;; note fall-through here :)
 newline:
         db 0xa, 0xd, "$"
 
-;;; ***
-;;; If this is non-zero we skip showing the user-number
-;;;
-SHOW_USER_MARKER:
-     db 0
-
         END

samples/delete.com

@@ -259,9 +259,6 @@ C_RAWIO_PROMPT:
         DB "  Echo should NOT be enabled.", 0x0a, 0x0d
         DB "  Press 'q' to proceed/complete this test.", 0x0a, 0x0d, "$"
 
-C_RAWIO_BUFFER:
-        DB 0x00, "$"
-
 C_RAWIO_SPINNER_1:
         DB "x", 0x08, "$"
 C_RAWIO_SPINNER_2:

samples/delete.z80

@@ -15,7 +15,6 @@
 
 FCB1:                EQU 0x5C
 DMA:                 EQU 0x80
-DMA_LEN:             EQU 128
 BDOS_ENTRY_POINT:    EQU 5
 BDOS_OUTPUT_STRING:  EQU 9
 BDOS_READ_FILE:      EQU 20
@@ -189,16 +188,11 @@ show_a_register:
         ret
 
 usage_message:
-        db "Usage: READ FILENAME.EXT"
-        ;; note fall-through here :)
-newline:
-        db 0xa, 0xd, "$"
+        db "Usage: READ FILENAME.EXT", 0xa, 0xd, "$"
 FAILURE:
         db "Unexpected value reading file at record $"
 
 OPEN_FAILED:
         db "opening the file failed.", 0x0a, 0x0d, "$"
 
-RECORD:
-        DB 0x00
 END