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ed: read initial contents in bufInit

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This commit is contained in:
Virgil Dupras 2019-07-14 12:19:37 -04:00
parent 797cbdcc95
commit 5669884508
2 changed files with 32 additions and 35 deletions
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58
apps/ed/buf.asm
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@ -7,43 +7,47 @@
; ;
; Maximum number of lines allowed in the buffer. ; Maximum number of lines allowed in the buffer.
.equ BUF_MAXLINES 0x800 .equ BUF_MAXLINES 0x800
; Size of our scratchpad
.equ BUF_PADMAXLEN 0x1000
; *** Variables *** ; *** Variables ***
; Number of lines currently in the buffer ; Number of lines currently in the buffer
.equ BUF_LINECNT BUF_RAMSTART .equ BUF_LINECNT BUF_RAMSTART
; List of words pointing to scratchpad offsets ; List of words pointing to scratchpad offsets
.equ BUF_LINES BUF_LINECNT+2 .equ BUF_LINES BUF_LINECNT+2
.equ BUF_RAMEND BUF_LINES+BUF_MAXLINES*2 ; size of file we read in bufInit. That offset is the beginning of our
; in-memory scratchpad.
.equ BUF_FSIZE BUF_LINES+BUF_MAXLINES*2
; The in-memory scratchpad
.equ BUF_PADLEN BUF_FSIZE+2
.equ BUF_PAD BUF_PADLEN+2
.equ BUF_RAMEND BUF_PAD+BUF_PADMAXLEN
; *** Code *** ; *** Code ***
; On initialization, we read the whole contents of target blkdev and add lines
; as we go.
bufInit: bufInit:
xor a ld hl, 0
ld (BUF_LINECNT), a ld (BUF_PADLEN), hl
ret ld ix, BUF_LINES
ld bc, 0 ; line count
; Add a new line with offset HL to the buffer .loop:
bufAddLine: call blkTell ; --> HL
push de call blkGetC
push hl jr nz, .loopend
ld hl, BUF_LINES ld (ix), l
ld de, (BUF_LINECNT) inc ix
add hl, de ld (ix), h
add hl, de ; twice, because two bytes per line inc ix
; HL now points to the specified line offset in memory inc bc
pop de ; what used to be in HL ends up in DE call ioGetLine
; line offset popped back in HL jr .loop
ld (hl), e .loopend:
inc hl ; HL currently has the result of the last blkTell
ld (hl), d ld (BUF_FSIZE), hl
; increase line count ld (BUF_LINECNT), bc
ld hl, (BUF_LINECNT)
inc hl
ld (BUF_LINECNT), hl
; our initial HL is in DE. Before we pop DE back, let's swap these
; two so that all registers are preserved.
ex de, hl
pop de
ret ret
; transform line index HL into its corresponding memory address in BUF_LINES ; transform line index HL into its corresponding memory address in BUF_LINES

9
apps/ed/main.asm
View File

@ -54,14 +54,7 @@ edMain:
ld hl, 0 ld hl, 0
ld (ED_CURLINE), hl ld (ED_CURLINE), hl
; Fill line buffer call bufInit
.fillLoop:
call blkTell ; --> HL
call blkGetC
jr nz, .mainLoop
call bufAddLine
call ioGetLine
jr .fillLoop
.mainLoop: .mainLoop:
ld a, ':' ld a, ':'