more work on reading SD card directory

src/dos_m65/dev_sdcard/fs_hvsr_read_dir.s

@@ -6,22 +6,15 @@
 
 fs_hvsr_read_dir_open:
 
-	; Read dirent structure into $1000 and then copy it to SD_DIRENT
-	; Starting at $1000 VIC sees chargen, so this should be a safe place
-	; Content of the original memory location will be preserved
+	; Open the directory
 
-	jsr fs_hvsr_dirent_swap
-
-	ldx #$00 ; file descriptor; we use $00 for reading directory
-	ldy #$10 ; target page number
-
-	lda #$11                          ; dos_opendir
+	lda #$12                          ; dos_opendir
 	sta HTRAP00
 	+nop
 
 	; XXX handle read errors
 
-	jsr fs_hvsr_dirent_swap
+	sta SD_DIR_DESC                   ; store directory descriptor  XXX invent better name
 
 	; Reset status to OK
 
@@ -51,31 +44,71 @@ fs_hvsr_read_dir_open:
 
 fs_hvsr_read_dir:
 
-	jsr fs_hvsr_dirent_swap
+	; Read dirent structure into $1000 and then copy it to SD_DIRENT
+	; Starting at $1000 VIC sees chargen, so this should be a safe place
+	; Content of the original memory location will be preserved
 
-	ldx #$00 ; file descriptor; we use $00 for reading directory
-	ldy #$10 ; target page number
+	jsr fs_hvsr_dirent_prepare
 
-	lda #$12                          ; dos_readdir
+	ldx SD_DIR_DESC                   ; directory descriptor
+	ldy #$10                          ; target page number
+
+	lda #$13                          ; dos_readdir
 	sta HTRAP00
 	+nop
 
-	; XXX handle read errors
-
-	sta $400
-	stx $401
-
 	jsr fs_hvsr_dirent_swap
 
+	; If nothing to read, output 'blocks free'
+
+	bcc fs_hvsr_read_dir_blocksfree
+
+	; Dirent structure - important fields:
+	; - $00-$3F - file name
+	; - $40     - file name length
+	; - $55     - file type and attributes
+
+	; Validate entry
+
+	; X check for directory!
+
+	lda SD_DIRENT+$40
+	sec
+	sbc #$04                           ; strip 4 bytes - for dot and extension
+	sta SD_DIRENT+$40
+	bmi fs_hvsr_read_dir               ; if name too short, try next entry
+	beq fs_hvsr_read_dir               ; if name too short, try next entry
+	cmp #$11
+	bcs fs_hvsr_read_dir               ; if stripped name is 17 characters or longer, try the next entry
+	sta SD_DIRENT+$40                  ; store corrected file name length
+
+	; Detect file type (+64 for read-only, +128 = damaged)
+	; 0  = not supported
+	; 1  = SEQ
+	; 2  = PRG
+	; 3  = USR
+	; 4  = REL
+	; 5  = DIR
+	; 6  = D67 ; CBM 2040 (DOS 1)               - disk image
+	; 6  = D64 ; CBM 1541 / 2031 / 3040 / 4040  - disk image
+	; 7  = D71 ; CBM 1571                       - disk image
+	; 8  = D81 ; CBM 1581                       - disk image
+	; 9  = D80 ; CBM 8050                       - disk image
+	; 10 = D81 ; CBM 8250 / 1001                - disk image
+	; 11 = D90 ; CBM D9060 / D9090              - hard disk image
+	; 12 = D1M ; CMD FD 2000 / 4000             - disk image (DD)
+	; 13 = D2M ; CMD FD 2000 / 4000             - disk image (HD)
+	; 14 = D2M ; CMD FD 4000                    - disk image (ED)
+	; 15 = DHD ; CMD HD                         - hard disk image
+
+
+	; Try to prepare output row
+
+
+	; XXX provide proper implementation here
 
 	jmp fs_hvsr_read_dir_blocksfree      ; XXX temporary
 
-	; Dirent structure:
-	; - 4 bytes - inode
-	; - 2 bytes - ('off' - not sure what's this)
-	; - 4 bytes - ('reclen' - is it file size?)
-	; - 2 bytes - type
-
 fs_hvsr_read_dir_blocksfree:
 
 	; Set pointer to '0 BLOCKS FREE.' line
@@ -95,11 +128,12 @@ fs_hvsr_read_dir_blocksfree:
 	lda #$00
 	sta SD_DIR_PHASE
 
-    ; .X = file descriptor
+	; Close the directory within the hypervisor  XXX maybe move it to close routine
 
-	; lda #$13                          ; dos_closedir
-	; sta HTRAP00
-	; +nop
+    ldx SD_DIR_DESC
+	lda #$14                          ; dos_closedir
+	sta HTRAP00
+	+nop
 
 	clc
 	rts
@@ -109,8 +143,22 @@ fs_hvsr_read_dir_blocksfree:
 ; Helper routines
 ;
 
+fs_hvsr_dirent_prepare:
+
+	ldx #$00
+	txa
+@1:
+	ldy $1000, x
+	sty SD_DIRENT, x
+	sta $1000, x
+	inx
+	bne @1
+
+	rts
+
 fs_hvsr_dirent_swap:
 
+	php
 	ldx #$00
 @1:
 	lda $1000, x
@@ -120,4 +168,5 @@ fs_hvsr_dirent_swap:
 	inx
 	bne @1
 
+	plp
 	rts