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/*
Copyright (C) 2025 Mikael Hildenborg
SPDX-License-Identifier: BSD-2-Clause
*/
#ifdef _HAVE_INITFINI_ARRAY
#define _init __libc_init_array
#define _fini __libc_fini_array
#endif
.equ MINKEEP, 0x10000
.global _BasePage
.weak _stksize
.global _HeapPtr
.global _heapbase
.global _atari_4ba_at_prg_start
.global _atari_4be_at_prg_start
.global __BSS_SEGMENT_END
.section ".init"
.global _init
.type _init,#function
_init:
move.l 4(a7),a0
move.l a0, _BasePage
/*
First do a quick jump into supervisor mode to get some needed pointers.
*/
move.l #super_init, -(a7)
move.w #0x26, -(a7)
trap #14
addq.l #6, a7
/*
Make an estimate for how much memory we need to reserve for environment and arguments.
*/
jsr estimate_env_and_args_memory | in atari-environ.c
| d0 contains the number of bytes we need to reserve for environment and arguments.
move.l d0, d7
/*
Init stack and heap.
The size of the stack and heap together is specified in _stksize.
The stack is set to point at the top of the reserved memory.
The heap is set to point at the bottom of the reserved memory.
Usage of _stksize (mintlib functionally compatible):
if _stksize is undefined, then all available memory is used.
if _stksize is 0, then MINKEEP memory is used.
if _stksize > 0 && < 4, then _stksize/4 of all memory is used.
if _stksize >= 4, then use that much memory.
if _stksize == -1, then all available memory is used.
if _stksize < -1, then use -_stksize memory.
*/
lea __BSS_SEGMENT_END, a2
add.l d7, a2 | environment and arguments
move.l a2, _heapbase
move.l a2, _HeapPtr
move.l _BasePage, a0
move.l 4(a0), d1 | mem top
sub.l a2, d1 | free mem
move.l d1, d6
lea _stksize, a1
cmpa.w #0, a1
jeq stksize_selected
move.l (a1), d0
jeq stksize_zero
jmi stksize_negative
stksize_positive:
moveq #4, d2
cmp.l d2, d0
jpl stksize_above_three
stksize_one_to_three:
lsr.l #2, d1
move.l d1, d2
1:
subq.w #1, d0
jeq stksize_selected
add.l d2, d1
jra 1b
stksize_zero:
move.l #MINKEEP, d1
jra stksize_selected
stksize_negative:
not.l d0
jeq stksize_selected | -1
addq.l #1, d0 | d0 = -_stksize
stksize_above_three:
move.l d0, d1
stksize_selected:
| adjust for memory needed for environment and arguments
add.l d7, d1
cmp.l d1, d6
jpl 1f
move.l d6, d1
1:
add.l a2, d1
bclr #0, d1 | even address.
move.l d1, a7
sub.l a0, d1 | mem from basepage to top.
| Shrink mem.
move.l d1, -(a7)
move.l a0, -(a7)
clr.w -(a7)
move.w #0x4a, -(a7) | Mshrink()
trap #1
lea 12(a7), a7
tst.l d0
jpl heap_setup_done
| Error, just quit with d0 as return code.
move.w d0,-(a7)
move.w #0x4c,-(a7)
trap #1
super_init:
| Init stuff that needs supervisor mode set.
move.l 0x4ba, _atari_4ba_at_prg_start
move.l 0x4be, _atari_4be_at_prg_start
rts
heap_setup_done:
pea __BSS_SEGMENT_END | storage space for environment and arguments
jsr setup_env_and_args | in atari-environ.c
| crtbegin.o follows here with global constructors etc. init.
.section ".fini"
/*
Empty.
*/
.bss
.lcomm _BasePage, 4
.lcomm _HeapPtr, 4
.lcomm _heapbase, 4
.lcomm _atari_4ba_at_prg_start, 4
.lcomm _atari_4be_at_prg_start, 4
.even
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