POSIX file I/O by Oliver Schmidt

git-svn-id: svn://svn.cc65.org/cc65/trunk@3457 b7a2c559-68d2-44c3-8de9-860c34a00d81

libsrc/apple2/filedes.s

@@ -0,0 +1,64 @@
+;
+; Oliver Schmidt, 30.12.2004
+;
+; File descriptor management for the POSIX I/O routines
+;
+
+        .include	"errno.inc"
+        .include	"fcntl.inc"
+        .include	"filedes.inc"
+
+getfd:
+        ; Check for handle >= 256
+        cpx	#$00
+        bne	error
+
+        ; Check for handle >= MAX_FDS
+        cmp	#MAX_FDS
+        bcs	error
+
+        .if	.sizeof(FD) = 4
+
+        ; Convert handle to fdtab slot
+        asl
+        asl
+
+        .else
+        .error	"Assertion failed"
+        .endif
+
+        ; Check for fdtab slot in use
+        tay
+        lda	fdtab + FD::REF_NUM,y
+        beq	error
+
+        ; Return success
+        clc
+        rts
+
+        ; Load errno code and return error
+error:  lda	#EINVAL
+        sec
+        rts
+
+        .data
+
+fdtab:  .if	.sizeof(FD) = 4
+
+        .byte	$80		; STDIN_FILENO ::REF_NUM
+        .byte	O_RDONLY	; STDIN_FILENO ::FLAGS
+        .addr	$0000		; STDIN_FILENO ::BUFFER
+
+        .byte	$80		; STDOUT_FILENO::REF_NUM
+        .byte	O_WRONLY	; STDOUT_FILENO::FLAGS
+        .addr	$0000		; STDOUT_FILENO::BUFFER
+
+        .byte	$80		; STDERR_FILENO::REF_NUM
+        .byte	O_WRONLY	; STDERR_FILENO::FLAGS
+        .addr	$0000		; STDERR_FILENO::BUFFER
+
+        .else
+        .error	"Assertion failed"
+        .endif
+
+        .res	(MAX_FDS - 3) * .sizeof(FD)