102 lines
2 KiB
ArmAsm
102 lines
2 KiB
ArmAsm
#
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/*
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* Raspberry Pi support library for the ACK
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* © 2013 David Given
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* This file is redistributable under the terms of the 3-clause BSD license.
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* See the file 'Copying' in the root of the distribution for the full text.
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*/
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! Declare segments (the order is important).
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.sect .text
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.sect .rom
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.sect .data
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.sect .bss
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.sect .text
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#define gp r15
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#define STACKSIZE 16*1024
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! MAIN ENTRY POINT
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!
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! When running as a kernel, our parameters are passed in in r0-r5, so
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! the startup sequence mustn't disturb these.
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begtext:
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! Set up system registers.
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lea gp, begtext
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st sp, .returnsp
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st lr, .returnlr
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! Wipe the bss. (I'm a little suprised that __m_a_i_n doesn't do this.)
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lea r6, begbss
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lea r7, endbss
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mov r8, #0
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_1:
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stb r8, (r6)
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addcmpb.lt r6, #1, r7, _1
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! Set up the new stack and save the kernel parameters to it.
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lea sp, .stack + STACKSIZE
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sub r0, gp ! pointer
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sub r1, gp ! pointer
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sub r2, gp ! pointer
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sub r3, gp ! pointer
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! r4-r5 are not pointers and don't need adjusting
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push r0-r5
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sub r0, sp, gp
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st r0, _gpu_parameters
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! Push standard parameters onto the stack and go.
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mov r0, #0
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push r0 ! envp
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push r0 ! argv
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push r0 ! argc
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! Call the language startup code.
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bl __m_a_i_n
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! Fall through to __exit if this returns.
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.define __exit
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__exit:
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ld sp, .returnsp
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ld lr, .returnlr
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b lr
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! Define symbols at the beginning of our various segments, so that we can find
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! them. (Except .text, which has already been done.)
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.define begtext, begdata, begbss
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.sect .data; begdata:
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.sect .rom; begrom:
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.sect .bss; begbss:
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! Some magic data. All EM systems need these.
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.define .trppc, .ignmask, _errno
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.comm .trppc, 4
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.comm .ignmask, 4
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.comm _errno, 4
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! We store the stack pointer and return address on entry so that we can
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! cleanly exit.
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.comm .returnsp, 4
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.comm .returnlr, 4
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! User pointer to the GPU kernel parameter block.
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.define _gpu_parameters
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.comm _gpu_parameters, 4
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! User stack.
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.comm .stack, STACKSIZE
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