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ed: take filename as an argument

This hard-binds ed to the filesystem (I liked the idea of working
only with blockdevs though...), but this is necessary for the
upcoming `w` command. We need some kind of way to tell the
destination to write to truncate itself.

This only has a meaning in the filesystem, but it's necessary to
let the file know that its registered file size has possibly
shrunk.

I thought of alternatives that would have allowed me to keep ed
blkdev-centered, but they were all too hackish to my own taste.

Hence, this new hard-bind on files.
This commit is contained in:
Virgil Dupras 2019-07-20 19:35:19 -04:00
parent fe15bafeca
commit 942d2a952d
6 changed files with 83 additions and 26 deletions

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@ -22,8 +22,9 @@ not listed here are either bugs or simply aren't implemented yet.
## Usage
`ed` is invoked from the shell with no argument. ed takes no argument.
It reads from the currently selected blkdev and writes to it.
`ed` is invoked from the shell with a single argument: the name of the file to
edit. If the file doesn't exist, `ed` errors out. If it exists, a prompt is
shown.
In normal mode, `ed` waits for a command and executes it. If the command is
invalid, a line with `?` is printed and `ed` goes back to waiting for a command.

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@ -40,8 +40,8 @@ bufInit:
ld ix, BUF_LINES
ld bc, 0 ; line count
.loop:
call blkTell ; --> HL
call blkGetC
call ioTell ; --> HL
call ioGetC
jr nz, .loopend
ld (ix), l
inc ix

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@ -6,11 +6,62 @@
.equ IO_MAXLEN 0x7f
; *** Variables ***
; Handle of the target file
.equ IO_FILE_HDL IO_RAMSTART
; block device targeting IO_FILE_HDL
.equ IO_BLK IO_FILE_HDL+FS_HANDLE_SIZE
; Buffer for lines read from I/O.
.equ IO_LINE IO_RAMSTART
.equ IO_LINE IO_BLK+BLOCKDEV_SIZE
.equ IO_RAMEND IO_LINE+IO_MAXLEN+1 ; +1 for null
; *** Code ***
; Given a file name in (HL), open that file in (IO_FILE_HDL) and open a blkdev
; on it at (IO_BLK).
ioInit:
call fsFindFN
ret nz
ld ix, IO_FILE_HDL
call fsOpen
ld de, IO_BLK
ld hl, .blkdev
jp blkSet
.fsGetC:
ld ix, IO_FILE_HDL
jp fsGetC
.fsPutC:
ld ix, IO_FILE_HDL
jp fsPutC
.blkdev:
.dw .fsGetC, .fsPutC
ioGetC:
push ix
ld ix, IO_BLK
call _blkGetC
pop ix
ret
ioPutC:
push ix
ld ix, IO_BLK
call _blkPutC
pop ix
ret
ioSeek:
push ix
ld ix, IO_BLK
call _blkSeek
pop ix
ret
ioTell:
push ix
ld ix, IO_BLK
call _blkTell
pop ix
ret
; Given an offset HL, read the line in IO_LINE, without LF and null terminates
; it. Make HL point to IO_LINE.
ioGetLine:
@ -19,11 +70,11 @@ ioGetLine:
push bc
ld de, 0 ; limit ourselves to 16-bit for now
xor a ; absolute seek
call blkSeek
call ioSeek
ld hl, IO_LINE
ld b, IO_MAXLEN
.loop:
call blkGetC
call ioGetC
jr nz, .loopend
or a ; null? hum, weird. same as LF
jr z, .loopend

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@ -31,11 +31,17 @@
;
; *** Requirements ***
; BLOCKDEV_SIZE
; FS_HANDLE_SIZE
; _blkGetC
; _blkPutC
; _blkSeek
; _blkTell
; addHL
; blkGetC
; blkSeek
; blkTell
; cpHLDE
; fsFindFN
; fsOpen
; fsGetC
; fsPutC
; intoHL
; printstr
; printcrlf
@ -49,6 +55,9 @@
.equ ED_RAMEND ED_CURLINE+2
edMain:
; because ed only takes a single string arg, we can use HL directly
call ioInit
ret nz
; diverge from UNIX: start at first line
ld hl, 0
ld (ED_CURLINE), hl

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@ -27,6 +27,7 @@
jp fsFindFN
jp fsOpen
jp fsGetC
jp fsPutC
jp cpHLDE
jp parseArgs
jp printstr
@ -37,9 +38,6 @@
jp printcrlf
jp stdioPutC
jp stdioReadLine
jp blkGetC
jp blkSeek
jp blkTell
#include "core.asm"
#include "err.h"

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@ -20,16 +20,14 @@
.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
.equ printcrlf 0x48
.equ stdioPutC 0x4b
.equ stdioReadLine 0x4e
.equ blkGetC 0x51
.equ blkSeek 0x54
.equ blkTell 0x57
.equ fsPutC 0x33
.equ cpHLDE 0x36
.equ parseArgs 0x39
.equ printstr 0x3c
.equ _blkGetC 0x3f
.equ _blkPutC 0x42
.equ _blkSeek 0x45
.equ _blkTell 0x48
.equ printcrlf 0x4b
.equ stdioPutC 0x4e
.equ stdioReadLine 0x51