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cc65/libsrc/atari/exec.s

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Implement exec() for Atari XDOS. - Adds new ENOEXEC error code, also used by Apple2 targets. - Maximum command line length is 40, incl. program name. This is an XDOS restriction. - testcode/lib/tinyshell.c has been extended to be able to run programs.
2016-06-13 18:40:01 +00:00
;
; Christian Groessler, 12-Jun-2016
;
; int __fastcall__ exec (const char* progname, const char* cmdline);
;
; supports only XDOS at the moment
.export _exec
.import popax
.import __dos_type
.import findfreeiocb
.import incsp2
.import excexit ; from crt0.s
.import SP_save ; from crt0.s
.ifdef UCASE_FILENAME
.import ucase_fn
.import addysp
.endif
.include "zeropage.inc"
.include "errno.inc"
.include "atari.inc"
Fix exec() for atarixl target. The final part of exec() called 'excexit' and only then restored the stack pointer to its value at program entry. 'excexit' does all cleanup (the same as '_exit()'), which means that on the atarixl target the ROM is banked in again. On big programs the 'SP_save' variable might reside at a high memory address which is no longer accessible after the ROM has been banked in. The change just moves the restoration of the stack pointer before the call to 'excexit'. Another change lets exec.s compile if UCASE_FILENAME is not defined. And some other small cleanups, also in open.s.
2016-06-15 21:52:16 +00:00
; area $0100 to $0128 might be in use (e.g. Hias' high speed patch)
CMDLINE_BUFFER = $0129 ; put progname + cmdline as one single string there
; alternatively:
;CMDLINE_BUFFER = $0480 ; put progname + cmdline as one single string there
Implement exec() for Atari XDOS. - Adds new ENOEXEC error code, also used by Apple2 targets. - Maximum command line length is 40, incl. program name. This is an XDOS restriction. - testcode/lib/tinyshell.c has been extended to be able to run programs.
2016-06-13 18:40:01 +00:00
CMDLINE_MAX = 40+3 ; max. length of drive + progname + cmdline
.code
notsupp:lda #ENOSYS ; "unsupported system call"
.byte $2C ; bit opcode, eats the next 2 bytes
noiocb: lda #EMFILE ; "too many open files"
jsr incsp2 ; clean up stack
Some improvements to Atari exec() after review.
2016-06-14 18:44:57 +00:00
seterr: jmp __directerrno
Implement exec() for Atari XDOS. - Adds new ENOEXEC error code, also used by Apple2 targets. - Maximum command line length is 40, incl. program name. This is an XDOS restriction. - testcode/lib/tinyshell.c has been extended to be able to run programs.
2016-06-13 18:40:01 +00:00
; entry point
_exec:
; save cmdline
sta ptr3
stx ptr3+1
ldy __dos_type
cpy #XDOS
bne notsupp
jsr findfreeiocb
bne noiocb
stx tmp4 ; remember IOCB index
; get program name
jsr popax
.ifdef UCASE_FILENAME
.ifdef DEFAULT_DEVICE
ldy #$80
.else
ldy #$00
.endif
sty tmp2 ; set flag for ucase_fn
jsr ucase_fn
bcc ucok1
invret: lda #EINVAL ; file name is too long
bne seterr
ucok1:
.endif ; defined UCASE_FILENAME
; copy program name and arguments to CMDLINE_BUFFER
sta ptr4 ; ptr4: pointer to program name
stx ptr4+1
ldy #0
; TODO: check stack ptr and and use min(CMDLINE_MAX,available_stack)
copyp: lda (ptr4),y
beq copypd
sta CMDLINE_BUFFER,y
iny
cpy #CMDLINE_MAX
bne copyp
; programe name too long
beq invret
Fix exec() for atarixl target. The final part of exec() called 'excexit' and only then restored the stack pointer to its value at program entry. 'excexit' does all cleanup (the same as '_exit()'), which means that on the atarixl target the ROM is banked in again. On big programs the 'SP_save' variable might reside at a high memory address which is no longer accessible after the ROM has been banked in. The change just moves the restoration of the stack pointer before the call to 'excexit'. Another change lets exec.s compile if UCASE_FILENAME is not defined. And some other small cleanups, also in open.s.
2016-06-15 21:52:16 +00:00
.ifndef UCASE_FILENAME
invret: lda #EINVAL
bne seterr
.endif
Implement exec() for Atari XDOS. - Adds new ENOEXEC error code, also used by Apple2 targets. - Maximum command line length is 40, incl. program name. This is an XDOS restriction. - testcode/lib/tinyshell.c has been extended to be able to run programs.
2016-06-13 18:40:01 +00:00
; file name copied, check for args
copypd: tya ; put Y into X (index into CMDLINE_BUFFER)
tax
lda ptr3
ora ptr3+1 ; do we have arguments?
beq copycd ; no
ldy #0
lda (ptr3),y ; get first byte of cmdline parameter
beq copycd ; nothing there...
lda #' ' ; add a space btw. progname and cmdline
bne copyc1
; copy args
copyc: lda (ptr3),y
beq copycd
iny
copyc1: sta CMDLINE_BUFFER,x
inx
cpx #CMDLINE_MAX
bne copyc
; progname + arguments too long
beq invret
invexe: jsr close
lda #XNTBIN
bne setmerr
copycd: lda #ATEOL
sta CMDLINE_BUFFER,x
; open the program file, read the first two bytes and compare them to $FF
ldx tmp4 ; get IOCB index
lda ptr4 ; ptr4 points to progname
sta ICBAL,x
lda ptr4+1
sta ICBAH,x
lda #OPNIN ; open for input
sta ICAX1,x
lda #OPEN
sta ICCOM,x
jsr CIOV
tya
.ifdef UCASE_FILENAME
ldy tmp3 ; get size
jsr addysp ; free used space on the stack
; the following 'bpl' depends on 'addysp' restoring A as last command before 'rts'
.endif ; defined UCASE_FILENAME
bpl openok
pha ; remember error code
jsr close ; close the IOCB (required even if open failed)
pla ; put error code back into A
setmerr:jmp __mappederrno ; update errno from OS specific error code in A
openok: lda #>buf
sta ICBAH,x ; set buffer address
lda #<buf
sta ICBAL,x
lda #0 ; set buffer length
sta ICBLH,x
lda #2
sta ICBLL,x
lda #GETCHR ; iocb command code
sta ICCOM,x
jsr CIOV ; read it
bmi invexe ; read operation failed, return error
lda ICBLL,x ; # of bytes read
cmp #2
bne invexe
lda #$FF ; check file format (need $FFFF at the beginning)
cmp buf
bne invexe
cmp buf+1
bne invexe
jsr close ; close program file
; program file appears to be available and good
; here's the point of no return
Fix exec() for atarixl target. The final part of exec() called 'excexit' and only then restored the stack pointer to its value at program entry. 'excexit' does all cleanup (the same as '_exit()'), which means that on the atarixl target the ROM is banked in again. On big programs the 'SP_save' variable might reside at a high memory address which is no longer accessible after the ROM has been banked in. The change just moves the restoration of the stack pointer before the call to 'excexit'. Another change lets exec.s compile if UCASE_FILENAME is not defined. And some other small cleanups, also in open.s.
2016-06-15 21:52:16 +00:00
ldx SP_save
txs ; reset stack pointer to what it was at program entry
A small rearrangement of instructions in Atari's exec() to let the comments make sense again.
2016-06-15 22:47:13 +00:00
lda tmp4 ; get IOCB index
Implement exec() for Atari XDOS. - Adds new ENOEXEC error code, also used by Apple2 targets. - Maximum command line length is 40, incl. program name. This is an XDOS restriction. - testcode/lib/tinyshell.c has been extended to be able to run programs.
2016-06-13 18:40:01 +00:00
pha ; and save it ('excexit' calls destructors and they might destroy tmp4)
Fix exec() for atarixl target. The final part of exec() called 'excexit' and only then restored the stack pointer to its value at program entry. 'excexit' does all cleanup (the same as '_exit()'), which means that on the atarixl target the ROM is banked in again. On big programs the 'SP_save' variable might reside at a high memory address which is no longer accessible after the ROM has been banked in. The change just moves the restoration of the stack pointer before the call to 'excexit'. Another change lets exec.s compile if UCASE_FILENAME is not defined. And some other small cleanups, also in open.s.
2016-06-15 21:52:16 +00:00
jsr excexit ; on atarixl this will enable the ROM again, making all high variables inaccessible
Implement exec() for Atari XDOS. - Adds new ENOEXEC error code, also used by Apple2 targets. - Maximum command line length is 40, incl. program name. This is an XDOS restriction. - testcode/lib/tinyshell.c has been extended to be able to run programs.
2016-06-13 18:40:01 +00:00
pla
tax ; IOCB index in X
lda #<CMDLINE_BUFFER
sta ICBAL,x ; address
lda #>CMDLINE_BUFFER
sta ICBAH,x
lda #0
sta ICBLL,x ; length shouldn't be random, but 0 is ok
sta ICBLH,x
sta ICAX1,x
sta ICAX2,x
lda #80 ; XDOS: run DUP command
sta ICCOM,x
jmp CIOV_org ; no way to display an error message in case of failure, and we will return to DOS
; close IOCB, index in X
.proc close
lda #CLOSE
sta ICCOM,x
jmp CIOV ; close IOCB
.endproc
.bss
buf: .res 2
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