initial work towards reading SD card directory

src/dos_m65/dev_sdcard/dev_sd_cmd_open.s

@@ -28,6 +28,15 @@ dev_sd_cmd_OPEN_EOI:
 
 dev_sd_cmd_OPEN_dir:
 
+	; XXX
+
+    ; .X = file descriptor
+    ; .Y = page of memory for output
+
+	; lda #$11                          ; dos_opendir
+	; sta HTRAP00
+	; +nop
+
 	; Reset status to OK
 
 	lda #$00

src/dos_m65/dev_sdcard/dev_sd_cmd_read.s

@@ -15,6 +15,20 @@ dev_sd_cmd_READ:
 	sec ; mark EOI
 	rts
 
+dev_sd_cmd_READ_dir:
+
+	; Dirent structure:
+	; - 4 bytes - inode
+	; - 2 bytes - ('off' - not sure what's this)
+	; - 4 bytes - ('reclen' - is it file size?)
+	; - 2 bytes - type
+
+    ; .X = file descriptor
+    ; .Y = page of memory for output
+
+	; lda #$12                          ; dos_readdir
+	; sta HTRAP00
+	; +nop
 
 dev_sd_cmd_READ_dir_blocksfree:
 
@@ -32,8 +46,14 @@ dev_sd_cmd_READ_dir_blocksfree:
 
 	; Mark end of directory
 
-	lda #$FF
+	lda #$00
 	sta SD_DIR_PHASE
 
+    ; .X = file descriptor
+
+	; lda #$13                          ; dos_closedir
+	; sta HTRAP00
+	; +nop
+
 	clc
 	rts

src/dos_m65/dev_sdcard/dev_sd_init.s

@@ -6,7 +6,7 @@
 
 dev_sd_init:
 
-	; Copy status string
+	; Copy initial status string
 
 	ldx #$00
 	stx SD_STATUS_IDX
@@ -23,6 +23,16 @@ dev_sd_init:
 	sta SD_STATUS_STR,x
 	bne @1
 
+	; Close all the files in the hypervisor, go to root directory
+
+	lda #$22                          ; dos_closeall
+	sta HTRAP00
+	+nop
+
+	lda #$36                          ; dos_cdrootdir
+	sta HTRAP00
+	+nop
+
 	; End of initialization
 
 	rts