fs: further adjust to previous blkdev refactoring

Previous refacoring broke all seek/tell within fs. fs handles now lost
the responsibility to keep track of current position. It's blkdev's job.

apps/zasm/glue.asm

@@ -31,11 +31,10 @@
 ; parseHex
 ; parseHexPair
 ; blkSel
+; blkSet
 ; fsFindFN
 ; fsOpen
 ; fsGetC
-; fsSeek
-; fsTell
 ; cpHLDE
 ; parseArgs
 ; _blkGetC

apps/zasm/io.asm

@@ -46,8 +46,10 @@
 .equ	IO_SAVED_POS	IO_OUT_BLK+BLOCKDEV_SIZE
 ; File handle for included source
 .equ	IO_INCLUDE_HDL	IO_SAVED_POS+2
+; blkdev for include file
+.equ	IO_INCLUDE_BLK	IO_INCLUDE_HDL+FS_HANDLE_SIZE
 ; see ioPutBack below
-.equ	IO_PUTBACK_BUF	IO_INCLUDE_HDL+FS_HANDLE_SIZE
+.equ	IO_PUTBACK_BUF	IO_INCLUDE_BLK+BLOCKDEV_SIZE
 .equ	IO_IN_INCLUDE	IO_PUTBACK_BUF+1
 .equ	IO_PC		IO_IN_INCLUDE+1
 ; Current lineno in top-level file
@@ -64,6 +66,9 @@ ioInit:
 	xor	a
 	ld	(IO_PUTBACK_BUF), a
 	ld	(IO_IN_INCLUDE), a
+	ld	de, IO_INCLUDE_BLK
+	ld	hl, _ioIncBlk
+	call	blkSet
 	jp	ioResetCounters
 
 ioGetC:
@@ -73,8 +78,8 @@ ioGetC:
 	call	ioInInclude
 	jr	z, .normalmode
 	; We're in "include mode", read from FS
-	ld	ix, IO_INCLUDE_HDL
-	call	fsGetC
+	ld	ix, IO_INCLUDE_BLK
+	call	_blkGetC
 	cp	0x0a		; newline
 	jr	nz, .notNewline
 	; We have newline. Increase lineno and return (the rest of the
@@ -182,8 +187,8 @@ _ioSeek:
 	jp	_blkSeek
 .include:
 	; We're in "include mode", seek in FS
-	ld	ix, IO_INCLUDE_HDL
-	jp	fsSeek		; returns
+	ld	ix, IO_INCLUDE_BLK
+	jp	_blkSeek	; returns
 
 _ioTell:
 	call	ioInInclude
@@ -193,8 +198,8 @@ _ioTell:
 	jp	_blkTell
 .include:
 	; We're in "include mode", tell from FS
-	ld	ix, IO_INCLUDE_HDL
-	jp	fsTell		; returns
+	ld	ix, IO_INCLUDE_BLK
+	jp	_blkTell	; returns
 
 ; Sets Z according to whether we're inside an include
 ioInInclude:
@@ -213,6 +218,9 @@ ioOpenInclude:
 	ld	(IO_IN_INCLUDE), a
 	ld	hl, 0
 	ld	(IO_INC_LINENO), hl
+	xor	a
+	ld	ix, IO_INCLUDE_BLK
+	call	_blkSeek
 	cp	a		; ensure Z
 	ret
 
@@ -229,3 +237,10 @@ ioLineNo:
 	pop	af
 	ret
 
+_ioIncGetC:
+	ld	ix, IO_INCLUDE_HDL
+	jp	fsGetC
+
+_ioIncBlk:
+	.dw	_ioIncGetC, unsetZ
+

doc/zasm.md

@@ -20,6 +20,7 @@ is configured to start at `0xe00`
     > fopn 0 hello.asm      ; open file in handle 0
     > zasm 1 3              ; assemble opened file and spit result in mmap
     > bsel 3                ; select mmap
+    > mptr e000             ; set memptr to mmap's beginning
     > peek 5
     210890CD3C              ; looking good
     > mptr 4200             ; hello.asm is configured to run from 0x4200

kernel/blockdev.asm

@@ -58,7 +58,7 @@ blkSel:
 
 	ld	hl, blkDevTbl
 	or	a		; cp 0
-	jr	z, .afterloop	; index is zero? don't loop
+	jr	z, .end		; index is zero? don't loop
 	push	bc		; <|
 	ld	b, a		;  |
 .loop:				;  |
@@ -66,7 +66,19 @@ blkSel:
 	call	addHL		;  |
 	djnz	.loop		;  |
 	pop	bc		; <|
-.afterloop:
+.end:
+	call	blkSet
+	pop	hl
+	pop	de
+	pop	af
+	ret
+
+; Setup blkdev handle in (DE) using routines at (HL).
+blkSet:
+	push	af
+	push	de
+	push	hl
+
 	; Write GETC
 	push	hl		; <|
 	call	intoHL		;  |

kernel/fs.asm

@@ -86,9 +86,8 @@
 .equ	FS_META_FNAME_OFFSET	6
 ; Size in bytes of a FS handle:
 ; * 4 bytes for starting offset of the FS block
-; * 2 bytes for current position relative to block's position
 ; * 2 bytes for file size
-.equ	FS_HANDLE_SIZE		8
+.equ	FS_HANDLE_SIZE		6
 .equ	FS_ERR_NO_FS		0x5
 .equ	FS_ERR_NOT_FOUND	0x6
 
@@ -390,76 +389,63 @@ fsOpen:
 	ld	(ix+2), a
 	ld	a, (FS_BLK+7)
 	ld	(ix+3), a
-	; Current pos
-	ld	hl, FS_METASIZE
-	ld	(ix+4), l
-	ld	(ix+5), h
 	; file size
 	ld      hl, (FS_META+FS_META_FSIZE_OFFSET)
-	ld	(ix+6), l
-	ld	(ix+7), h
+	ld	(ix+4), l
+	ld	(ix+5), h
 	pop	af
 	pop	hl
 	ret
 
-; Place FS blockdev at proper position for file handle in (IX).
+; Place FS blockdev at proper position for file handle in (IX) at position HL.
 fsPlaceH:
 	push	af
-	push	bc
-	push	hl
 	push	de
+	push	hl
+	; Move fsdev to beginning of block
 	ld	e, (ix)
 	ld	d, (ix+1)
 	ld	l, (ix+2)
 	ld	h, (ix+3)
-	ld	c, (ix+4)
-	ld	b, (ix+5)
-	add	hl, bc
-	jr	nc, .nocarry
-	inc	de
-.nocarry:
 	ld	a, BLOCKDEV_SEEK_ABSOLUTE
 	call	fsblkSeek
-	pop	de
+
+	; skip metadata
+	ld	a, BLOCKDEV_SEEK_FORWARD
+	ld	hl, FS_METASIZE
+	call	fsblkSeek
+
 	pop	hl
-	pop	bc
-	pop	af
-	ret
+	pop	de
 
-; Advance file handle in (IX) by one byte
-fsAdvanceH:
-	push	af
-	inc	(ix+4)
-	jr	nz, .end
-	inc	(ix+5)
-.end:
+	; go to specified pos
+	ld	a, BLOCKDEV_SEEK_FORWARD
+	call	fsblkSeek
 	pop	af
 	ret
 
-; Sets Z according to whether file handle at (IX) is within bounds, that is, if
-; current position is smaller than file size.
-fsHandleWithinBounds:
-	push	hl
+; Advance file handle in (IX) by one byte
+; Sets Z according to whether HL is within bounds for file handle at (IX), that
+; is, if it is smaller than file size.
+fsWithinBounds:
 	push	de
-	; current pos in HL, adjusted to remove FS_METASIZE
-	call	fsTell
 	; file size
-	ld	e, (ix+6)
-	ld	d, (ix+7)
+	ld	e, (ix+4)
+	ld	d, (ix+5)
 	call	cpHLDE
 	pop	de
-	pop	hl
 	jr	nc, .outOfBounds	; HL >= DE
 	cp	a			; ensure Z
 	ret
 .outOfBounds:
 	jp	unsetZ			; returns
 
-; Read a byte in handle at (IX), put it into A and advance the handle's
-; position.
+; Read a byte in handle at (IX) at position HL and put it into A.
 ; Z is set on success, unset if handle is at the end of the file.
 fsGetC:
-	call	fsHandleWithinBounds
+	ld	a, h
+	ld	a, l
+	call	fsWithinBounds
 	jr	z, .proceed
 	; We want to unset Z, but also return 0 to ensure that a GetC that
 	; doesn't check Z doesn't end up with false data.
@@ -467,35 +453,14 @@ fsGetC:
 	jp	unsetZ		; returns
 .proceed:
 	call	fsPlaceH
-	call	fsblkGetC
-	ret	nz		; error, don't advance
-	; increase current pos
-	jp	fsAdvanceH	; returns
+	jp	fsblkGetC	; returns
 
 ; Write byte A in handle (IX) and advance the handle's position.
 ; Z is set on success, unset if handle is at the end of the file.
 ; TODO: detect end of block alloc
 fsPutC:
 	call	fsPlaceH
-	call	fsblkPutC
-	jp	fsAdvanceH	; returns
-
-; Sets position of handle (IX) to HL. This position does *not* include metadata.
-; It is an offset that starts at actual data.
-; Sets Z if offset is within bounds, unsets Z if it isn't.
-fsSeek:
-	ld	a, FS_METASIZE
-	call	addHL
-	ld	(ix+4), l
-	ld	(ix+5), h
-	ret
-
-; Returns current position of file handle at (IX) in HL.
-fsTell:
-	ld	l, (ix+4)
-	ld	h, (ix+5)
-	ld	a, FS_METASIZE
-	jp	subHL		; returns
+	jp	fsblkPutC	; returns
 
 ; Mount the fs subsystem upon the currently selected blockdev at current offset.
 ; Verify is block is valid and error out if its not, mounting nothing.

tools/emul/shell/shell.c

@@ -120,6 +120,8 @@ static void io_write(int unused, uint16_t addr, uint8_t val)
             fsdev_ptr |= val;
             fsdev_addr_lvl = 0;
         }
+    } else {
+        fprintf(stderr, "Out of bounds I/O write: %d / %d (0x%x)\n", addr, val, val);
     }
 }
 

tools/emul/shell/shell_.asm

@@ -23,11 +23,10 @@
 	jp	parseHex
 	jp	parseHexPair
 	jp	blkSel
+	jp	blkSet
 	jp	fsFindFN
 	jp	fsOpen
 	jp	fsGetC
-	jp	fsSeek
-	jp	fsTell
 	jp	cpHLDE
 	jp	parseArgs
 	jp	printstr

tools/emul/shell/user.h

@@ -16,15 +16,14 @@
 .equ    parseHex       0x1e
 .equ    parseHexPair   0x21
 .equ    blkSel         0x24
-.equ    fsFindFN       0x27
-.equ    fsOpen         0x2a
-.equ    fsGetC         0x2d
-.equ    fsSeek         0x30
-.equ    fsTell         0x33
-.equ    cpHLDE         0x36
-.equ    parseArgs      0x39
-.equ    printstr       0x3c
-.equ    _blkGetC       0x3f
-.equ    _blkPutC       0x42
-.equ    _blkSeek       0x45
-.equ    _blkTell       0x48
+.equ    blkSet         0x27
+.equ    fsFindFN       0x2a
+.equ    fsOpen         0x2d
+.equ    fsGetC         0x30
+.equ    cpHLDE         0x33
+.equ    parseArgs      0x36
+.equ    printstr       0x39
+.equ    _blkGetC       0x3c
+.equ    _blkPutC       0x3f
+.equ    _blkSeek       0x42
+.equ    _blkTell       0x45

tools/emul/zasm/glue.asm

@@ -21,11 +21,10 @@ jp	findchar
 jp	parseHex
 jp	parseHexPair
 jp	blkSel
+jp	blkSet
 jp	fsFindFN
 jp	fsOpen
 jp	fsGetC
-jp	fsSeek
-jp	fsTell
 jp	cpHLDE
 jp	parseArgs
 jp	_blkGetC

tools/emul/zasm/user.h

@@ -16,14 +16,13 @@
 .equ    parseHex       0x1e
 .equ    parseHexPair   0x21
 .equ    blkSel         0x24
-.equ    fsFindFN       0x27
-.equ    fsOpen         0x2a
-.equ    fsGetC         0x2d
-.equ    fsSeek         0x30
-.equ    fsTell         0x33
-.equ    cpHLDE         0x36
-.equ    parseArgs      0x39
-.equ    _blkGetC       0x3c
-.equ    _blkPutC       0x3f
-.equ    _blkSeek       0x42
-.equ    _blkTell       0x45
+.equ    blkSet         0x27
+.equ    fsFindFN       0x2a
+.equ    fsOpen         0x2d
+.equ    fsGetC         0x30
+.equ    cpHLDE         0x33
+.equ    parseArgs      0x36
+.equ    _blkGetC       0x39
+.equ    _blkPutC       0x3c
+.equ    _blkSeek       0x3f
+.equ    _blkTell       0x42

tools/tests/zasm/test7.asm

@@ -16,17 +16,16 @@
 .equ    parseHex       0x1e
 .equ    parseHexPair   0x21
 .equ    blkSel         0x24
-.equ    fsFindFN       0x27
-.equ    fsOpen         0x2a
-.equ    fsGetC         0x2d
-.equ    fsSeek         0x30
-.equ    fsTell         0x33
-.equ    cpHLDE         0x36
-.equ    parseArgs      0x39
-.equ    _blkGetC       0x3c
-.equ    _blkPutC       0x3f
-.equ    _blkSeek       0x42
-.equ    _blkTell       0x45
+.equ    blkSet         0x27
+.equ    fsFindFN       0x2a
+.equ    fsOpen         0x2d
+.equ    fsGetC         0x30
+.equ    cpHLDE         0x33
+.equ    parseArgs      0x36
+.equ    _blkGetC       0x39
+.equ    _blkPutC       0x3c
+.equ    _blkSeek       0x3f
+.equ    _blkTell       0x42
 
 #include "err.h"
 #include "zasm/const.asm"