diff --git a/src/dos_m65/,aliases_dos.s b/src/dos_m65/,aliases_dos.s
index 9a7ec1e6..528acf34 100644
--- a/src/dos_m65/,aliases_dos.s
+++ b/src/dos_m65/,aliases_dos.s
@@ -35,16 +35,19 @@
 	!addr IDX1_TALKER      = $8012 ; talker idx, >=$80 = none
 	!addr IDX2_TALKER      = $8013 ; talker idx * 2, >=$80 = none - for calling routines via vector table
 
+	; Parameters for utilities
+
+	!addr PAR_FSIZE_BLOCKS = $8014 ; 2 bytes - file size in blocks
+	!addr PAR_FSIZE_BYTES  = $8016 ; 4 bytes - file size in bytes
+
 	; Various temporary data
 
-	!addr XX_DIR_PHASE     = $8014 ; directory output phase, values deponds on device driver
-	!addr SD_DIR_PHASE     = $8014 ; - SD card
-	!addr FD_DIR_PHASE     = $8015 ; - floppy
-	!addr RD_DIR_PHASE     = $8016 ; - ram disk
+	!addr XX_DIR_PHASE     = $801A ; directory output phase, values deponds on device driver
+	!addr SD_DIR_PHASE     = $801A ; - SD card
+	!addr FD_DIR_PHASE     = $801B ; - floppy
+	!addr RD_DIR_PHASE     = $801C ; - ram disk
 
-
-
-	; Free space: $8014-$8063
+	; Free space: $801D-$8063
 
 	!addr SD_ACPTR_helper  = $8052 ; subroutine in RAM to read a byte
 	!addr code_LDA_01      = $8052 ; - LDA instruction
diff --git a/src/dos_m65/dev_sdcard/fs_hvsr_read_dir.s b/src/dos_m65/dev_sdcard/fs_hvsr_read_dir.s
index f8d04c80..f4963269 100644
--- a/src/dos_m65/dev_sdcard/fs_hvsr_read_dir.s
+++ b/src/dos_m65/dev_sdcard/fs_hvsr_read_dir.s
@@ -212,34 +212,36 @@ fs_hvsr_read_dir:
 	sta SD_DIRENT+$80
 	sta SD_DIRENT+$81
 	
-	lda SD_DIRENT+$53                  ; XXX calculate length in blocks instead
-	sta SD_DIRENT+$82
-	lda SD_DIRENT+$54
-	sta SD_DIRENT+$83	
-
-	bra @len_done                      ; XXX if size above 9999, force maximum possible length
-
-@len_max:
-
-	lda #<9999
-	sta SD_DIRENT+$82
-	lda #>9999
-	sta SD_DIRENT+$83
-
-@len_done:
-
 	ldx SD_DIRENT+$40                  ; make sure file name is terminated by 0
 	lda #$00
 	sta SD_DIRENT, x
 
-	ldx #$04                           ; XXX put correct amount of spaces depending on number size
+	lda SD_DIRENT+$52                  ; calculate file length in blocks to display
+	sta PAR_FSIZE_BYTES+0
+	lda SD_DIRENT+$53
+	sta PAR_FSIZE_BYTES+1
+	lda SD_DIRENT+$54
+	sta PAR_FSIZE_BYTES+2
+	lda SD_DIRENT+$55
+	sta PAR_FSIZE_BYTES+3
+
+	jsr util_dir_filesize_bytes
+
+	lda PAR_FSIZE_BLOCKS+0
+	sta SD_DIRENT+$82
+	lda PAR_FSIZE_BLOCKS+1
+	sta SD_DIRENT+$83
+
 	lda #' '
+	ldx #$04                           ; indent number of blocks
+@lpindent1:
+	dey
+	bmi @lpindent1_done
 	sta SD_DIRENT+$80, x
 	inx
-	sta SD_DIRENT+$80, x
-	inx
-	sta SD_DIRENT+$80, x
-	inx
+	bra @lpindent1
+
+@lpindent1_done:
 
 	lda #$22                           ; opening quote
 	sta SD_DIRENT+$80, x
diff --git a/src/dos_m65/utils/util_dir_filesize.s b/src/dos_m65/utils/util_dir_filesize.s
index a9f94386..ed399b90 100644
--- a/src/dos_m65/utils/util_dir_filesize.s
+++ b/src/dos_m65/utils/util_dir_filesize.s
@@ -2,8 +2,96 @@
 ; Adapt the file size for displaying in a directory list
 
 
-util_dir_filesize:
+util_dir_filesize_bytes: ; preserves .X
 
-	; XXX provide implementation
+	; Convert file size in bytes (32-bit value) to blocks, afterwards
+	; continue processing in 'util_dir_filesize_blocks'
 
+	; XXX temporary - calculate size in 254-byte blocks
+
+	lda PAR_FSIZE_BYTES+1
+	sta PAR_FSIZE_BLOCKS+0
+	lda PAR_FSIZE_BYTES+2
+	sta PAR_FSIZE_BLOCKS+1
+
+	; FALLTROUGH
+
+util_dir_filesize_blocks: ; preserves .X
+
+	; Take file size in blocks (16-bit value), clip to max 9999,
+	; return in .Y the amount of spaces needed for indentation
+	
+	lda PAR_FSIZE_BLOCKS+1
+	cmp #>9999
+	beq @cmp_9999_p2
+	bcs util_dir_filesize_max
+	bcc @size_ok
+
+@cmp_9999_p2:
+
+	lda PAR_FSIZE_BLOCKS+0
+	cmp #<9999
+	bcs util_dir_filesize_max
+
+@size_ok:
+	
+	lda PAR_FSIZE_BLOCKS+1
+	beq @size_123
+
+@size_34:  ; file size is 256 or above (3 or 4 digits)
+
+	cmp #>1000
+	beq @cmp_1000_p2
+	bcs util_dir_filesize_4
+	bra util_dir_filesize_3
+
+@cmp_1000_p2:
+
+	lda PAR_FSIZE_BLOCKS+0
+	cmp #<1000
+	bcs util_dir_filesize_4
+	bra util_dir_filesize_3
+
+@size_123: ; file size is 255 or below (1, 2, or 3 digits)
+
+	lda PAR_FSIZE_BLOCKS+0
+	cmp #10
+	bcs util_dir_filesize_23
+
+	; FALLTROUGH
+
+util_dir_filesize_1:  ; file size needs 1 digit
+
+	ldy #$03
+	rts
+
+util_dir_filesize_23: ; file size needs 2 or 3 digits, size in .A
+
+	cmp #100
+	bcs util_dir_filesize_3
+
+	; FALLTROUGH
+
+util_dir_filesize_2:  ; file size needs 2 digits
+
+	ldy #$02
+	rts
+
+util_dir_filesize_3: ; file size needs 3 digits
+
+	ldy #$01
+	rts
+
+util_dir_filesize_max:
+
+	lda #<9999
+	sta PAR_FSIZE_BLOCKS+0
+	lda #>9999
+	sta PAR_FSIZE_BLOCKS+1
+
+	; FALLTROUGH
+
+util_dir_filesize_4: ; file size needs 4 digits
+
+	ldy #$00
 	rts