49644a2c39
Port to the really neat 68010 based board at https://rosco-m68k.com/ Port Features: -10Mhz 68010 -1MB ram -Dual UART + timer implemented as a 68c681 chip -timer running at 1Khz, UART A for console -interrupt driven RX support Some amount of extending of the 68k exceptinon code was needed to support the autovectored irqs that the 68681 uart uses. Added build system support for 68010.
66 lines
1.3 KiB
ArmAsm
66 lines
1.3 KiB
ArmAsm
/*
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* Copyright (c) 2021 Travis Geiselbrecht
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*
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* Use of this source code is governed by a MIT-style
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* license that can be found in the LICENSE file or at
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* https://opensource.org/licenses/MIT
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*/
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#include <lk/asm.h>
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.section .text.boot
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FUNCTION(_start)
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#if ARCH_DO_RELOCATION
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lea %pc@(_start),%a0 // load the current address using PC relative addressing mode
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movl #_start,%a1 // load the same symbol absolutely
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cmpal %a0,%a1
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beqs bss_clear
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// load the end address for loop termination
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movl #_end,%a2
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// copy forwards
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// NOTE: assumes the source and target do not overlap
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0:
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movel %a0@+,%a1@+
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cmpal %a1,%a2
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bne 0b
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// branch to the new location
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movl #bss_clear,%a0
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jmp %a0@
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#endif
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// clear bss
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bss_clear:
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lea __bss_start,%a0
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lea __bss_end,%a1
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cmpl %a0,%a1
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beqs 1f
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// zero 4 bytes at a time
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0:
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clrl %a0@+
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cmpal %a1,%a0
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bne 0b
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1:
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// load the initial stack pointer
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lea _default_stack_top,%sp
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// branch into C land with 4 zeroed args
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clrl %sp@-
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clrl %sp@-
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clrl %sp@-
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clrl %sp@-
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jsr lk_main
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// if we return from main just loop forever
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bra .
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END_FUNCTION(_start)
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.bss
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.align 4
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_default_stack_base:
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.skip 4096
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_default_stack_top:
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