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172 lines
3.9 KiB
ArmAsm
172 lines
3.9 KiB
ArmAsm
;
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; Ullrich von Bassewitz, 16.11.2002
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;
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; int open (const char* name, int flags, ...); /* May take a mode argument */
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;
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.export _open
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.import addysp, popax
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.import scratch, fnparse, fncomplete, fnset
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.import opencmdchannel, closecmdchannel, readdiskerror
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.import __errno, __oserror
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.import fnunit
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.importzp sp, tmp2, tmp3
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.include "errno.inc"
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.include "fcntl.inc"
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.include "cbm.inc"
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.include "filedes.inc"
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;--------------------------------------------------------------------------
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; initstdout: Open the stdout and stderr file descriptors for the screen.
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.proc _open
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cpy #4 ; correct # of arguments (bytes)?
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beq parmok ; parameter count ok
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tya ; parm count < 4 shouldn't be needed to be...
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sec ; ...checked (it generates a c compiler warning)
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sbc #4
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tay
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jsr addysp ; fix stack, throw away unused parameters
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; Parameters ok. Pop the flags and save them into tmp3
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parmok: jsr popax ; Get flags
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sta tmp3
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; Get the filename from stack and parse it. Bail out if is not ok
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jsr popax ; Get name
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jsr fnparse ; Parse it
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cmp #0
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bne error ; Bail out if problem with name
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; Get a free file handle and remember it in tmp2
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jsr freefd
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bcs nofile
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stx tmp2
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; Check the flags. We cannot have:
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;
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; - both, read and write flags set
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; - the append flag set
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;
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lda tmp3
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and #O_RDWR
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beq invflags ; Neither read nor write
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cmp #O_RDWR
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beq invflags ; Jump if both set
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cmp #O_RDONLY
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beq doread
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; Write bit is set. We cannot open a file for writing without creating it,
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; so check for the O_CREAT bit.
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lda tmp3
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and #O_CREAT
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beq invflags
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; If O_TRUNC is set, scratch the file, but ignore any errors
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lda tmp3
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and #O_TRUNC
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beq notrunc
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jsr scratch
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; Complete the the file name
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notrunc:
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lda #'w'
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jsr fncomplete
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; Setup the real open flags
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lda #LFN_WRITE
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bne common
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; Read bit is set. Add an 'r' to the name
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doread: lda #'r'
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jsr fncomplete
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lda #LFN_READ
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; Common read/write code. Flags in A, handle in tmp2
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common: sta tmp3
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jsr fnset ; Set the file name
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lda tmp2
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clc
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adc #LFN_OFFS
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ldx fnunit
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tay ; Use the LFN also as SA
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jsr SETLFS ; Set the file params
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jsr OPEN
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bcs error
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; Open the the drive command channel and read it
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ldx fnunit
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jsr opencmdchannel
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bne closeandexit
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ldx fnunit
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jsr readdiskerror
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bne closeandexit ; Branch on error
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; File is open. Mark it as open in the table
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ldx tmp2
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lda tmp3
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sta fdtab,x
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lda fnunit
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sta unittab,x ; Remember
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; Done. Return the handle in a/x
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txa ; Handle
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ldx #0
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rts
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; Error entry: No more file handles
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nofile: lda #1 ; Too many open files
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; Error entry. Error code is in A.
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error: sta __oserror
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errout: lda #$FF
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tax ; Return -1
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rts
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; Error entry: Invalid flag parameter
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invflags:
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lda #EINVAL
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sta __errno
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lda #0
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sta __errno+1
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beq errout
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; Error entry: Close the file and exit
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closeandexit:
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pha
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lda tmp2
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clc
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adc #LFN_OFFS
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jsr CLOSE
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ldx fnunit
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jsr closecmdchannel
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pla
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bne error ; Branch always
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.endproc
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