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0ee9b2e446
So far the INIT segment was run from the later heap+stack. Now the INIT segment is run from the later BSS. The background is that so far the INIT segment was pretty small (from $80 to $180 bytes). But upcoming changes will increase the INIT segment in certain scenarios up to ~ $1000 bytes. So programs with very limited heap+stack might just not been able to move the INIT segment to its run location. But moving the INIT segment to the later BSS allows it to occupy the later BSS+heap+stack. In order to allow that the constructors are _NOT_ allowed anymore to access the BSS. Rather they must use the DATA segment or the new INITBSS segment. The latter isn't cleared at any point so the constructors may use it to expose values to the main program. However they must make sure to always write the values as they are not pre-initialized.
119 lines
2.7 KiB
ArmAsm
119 lines
2.7 KiB
ArmAsm
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; Ullrich von Bassewitz, 16.11.2002
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;
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; int write (int fd, const void* buf, unsigned count);
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;
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.export _write
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.constructor initstdout
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.import SETLFS, OPEN, CKOUT, BSOUT, READST, CLRCH
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.import rwcommon
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.importzp sp, ptr1, ptr2, ptr3
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.include "cbm.inc"
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.include "errno.inc"
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.include "fcntl.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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.segment "INIT"
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.proc initstdout
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lda #STDOUT_FILENO + LFN_OFFS
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jsr @L1
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lda #STDERR_FILENO + LFN_OFFS
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@L1: ldx #CBMDEV_SCREEN
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ldy #$FF
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jsr SETLFS
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jmp OPEN ; Will always succeed
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.endproc
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;--------------------------------------------------------------------------
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; _write
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.code
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.proc _write
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jsr rwcommon ; Pop params, check handle
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bcs invalidfd ; Invalid handle
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; Check if the LFN is valid and the file is open for writing
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adc #LFN_OFFS ; Carry is already clear
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tax
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lda fdtab-LFN_OFFS,x; Get flags for this handle
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and #LFN_WRITE ; File open for writing?
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beq invalidfd
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; Valid lfn. Make it the output file
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jsr CKOUT
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bcc @L2
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@error: jmp __mappederrno ; Store into __oserror, map to errno, return -1
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; Output the next character from the buffer
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@L0: ldy #0
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lda (ptr2),y
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inc ptr2
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bne @L1
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inc ptr2+1 ; A = *buf++;
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@L1: jsr BSOUT
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; Check the status
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pha
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jsr READST
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lsr a ; Bit zero is write timeout
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bne devnotpresent2
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pla
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bcs @L3
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; Count characters written
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inc ptr3
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bne @L2
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inc ptr3+1
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; Decrement count
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@L2: inc ptr1
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bne @L0
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inc ptr1+1
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bne @L0
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; Wrote all chars or disk full. Close the output channel
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@L3: jsr CLRCH
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; Clear _oserror and return the number of chars written
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lda #0
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sta __oserror
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lda ptr3
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ldx ptr3+1
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rts
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; Error entry: Device not present
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devnotpresent2:
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pla
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devnotpresent:
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lda #ENODEV
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jmp __directerrno ; Sets _errno, clears _oserror, returns -1
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; Error entry: The given file descriptor is not valid or not open
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invalidfd:
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lda #EBADF
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jmp __directerrno ; Sets _errno, clears _oserror, returns -1
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.endproc
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