| 1 | /* dlentry.s |
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| 2 | * |
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| 3 | * $Id$ |
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| 4 | * |
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| 5 | * This file contains the entry veneer for RTEMS programs |
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| 6 | * downloaded to the eth-comm board. |
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| 7 | * |
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| 8 | * This file was written by Jay Monkman (jmonkman@fracsa.com) |
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| 9 | * It was based on the dlentry.s file for the Papyrus BSP, |
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| 10 | * written by: |
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| 11 | * |
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| 12 | * Author: Andrew Bray <andy@i-cubed.co.uk> |
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| 13 | * |
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| 14 | * COPYRIGHT (c) 1995 by i-cubed ltd. |
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| 15 | * |
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| 16 | * To anyone who acknowledges that this file is provided "AS IS" |
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| 17 | * without any express or implied warranty: |
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| 18 | * permission to use, copy, modify, and distribute this file |
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| 19 | * for any purpose is hereby granted without fee, provided that |
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| 20 | * the above copyright notice and this notice appears in all |
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| 21 | * copies, and that the name of i-cubed limited not be used in |
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| 22 | * advertising or publicity pertaining to distribution of the |
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| 23 | * software without specific, written prior permission. |
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| 24 | * i-cubed limited makes no representations about the suitability |
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| 25 | * of this software for any purpose. |
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| 26 | * |
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| 27 | */ |
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| 28 | |
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| 29 | #include <rtems/asm.h> |
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| 30 | |
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| 31 | /* |
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| 32 | * The initial stack is set to run BELOW the code base address. |
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| 33 | * (between the vectors and text sections) |
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| 34 | * |
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| 35 | * All the entry veneer has to do is to clear the BSS. |
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| 36 | */ |
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| 37 | |
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| 38 | /* |
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| 39 | * GDB likes to have debugging information for the entry veneer. |
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| 40 | * Here is some DWARF information. |
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| 41 | */ |
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| 42 | /* |
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| 43 | * There was some debugging info here, but I removed it because I |
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| 44 | * couldn't get it to work. It isn't really necessary as far as I |
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| 45 | * can tell. It should still be in the papyrus BSP. -Jay |
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| 46 | */ |
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| 47 | |
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| 48 | /* |
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| 49 | * On entry to download_entry, R3 will hold a pointer to a Board Info |
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| 50 | * Block (boardinfo_t). This should be copied as soon as possible |
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| 51 | * to the global M860_binfo. (The block should be copied, _NOT_ |
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| 52 | * the pointer) |
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| 53 | */ |
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| 54 | |
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| 55 | .section ".entry" /* This might have to be the first thing in the |
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| 56 | * text section. At one time, it had to be |
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| 57 | * first, but I don't believe it is true |
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| 58 | * andy more. */ |
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| 59 | PUBLIC_VAR (start) |
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| 60 | SYM(start): |
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| 61 | bl .startup |
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| 62 | base_addr: |
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| 63 | |
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| 64 | /* |
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| 65 | * Parameters from linker |
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| 66 | */ |
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| 67 | toc_pointer: |
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| 68 | .long s.got |
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| 69 | bss_length: |
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| 70 | .long bss.size |
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| 71 | bss_addr: |
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| 72 | .long bss.start |
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| 73 | |
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| 74 | PUBLIC_VAR (text_addr) |
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| 75 | text_addr: |
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| 76 | .long text.start |
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| 77 | |
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| 78 | PUBLIC_VAR (text_length) |
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| 79 | text_length: |
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| 80 | .long text.size |
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| 81 | |
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| 82 | /* |
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| 83 | * Initialization code |
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| 84 | */ |
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| 85 | .startup: |
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| 86 | /* Get start address */ |
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| 87 | mflr r1 |
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| 88 | |
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| 89 | /* clear the bss section */ |
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| 90 | bl bssclr |
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| 91 | |
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| 92 | /* |
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| 93 | * Copy the Board Info Block |
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| 94 | */ |
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| 95 | .extern SYM(M860_binfo) |
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| 96 | lis r6, SYM(M860_binfo)@ha |
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| 97 | addi r6, r6, SYM(M860_binfo)@l |
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| 98 | |
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| 99 | lhz r4, 0(r3) /* Load the size of the block */ |
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| 100 | rlwinm. r4, r4, 30, 0x3fffffff /* get number of words */ |
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| 101 | |
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| 102 | mtctr r4 |
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| 103 | |
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| 104 | cpy_b: lwz r5, 0(r3) /* In with the old ... */ |
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| 105 | stw r5, 0(r6) /* ... Out with the new */ |
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| 106 | addi r6, r6, 0x4 /* Go to the next word */ |
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| 107 | addi r3, r3, 0x4 |
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| 108 | bdnz cpy_b /* decrement counter and loop */ |
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| 109 | |
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| 110 | /* |
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| 111 | * C_setup. |
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| 112 | */ |
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| 113 | |
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| 114 | /* set toc */ |
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| 115 | lwz r2, toc_pointer-base_addr(r1) |
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| 116 | |
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| 117 | /* Set up stack pointer = beginning of text section - 56 */ |
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| 118 | addi r1, r1, -56-4 |
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| 119 | |
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| 120 | lis r9, 0xff00 |
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| 121 | addi r10, 0, -16384 |
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| 122 | sth r10, 0x950(r9) |
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| 123 | |
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| 124 | lis r9, 0x0000 |
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| 125 | addi r9, r9, 0x0007 |
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| 126 | mtspr 0x9e, r9 |
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| 127 | |
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| 128 | lis r5,environ@ha |
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| 129 | la r5,environ@l(r5) /* environp */ |
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| 130 | li r4, 0 /* argv */ |
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| 131 | li r3, 0 /* argc */ |
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| 132 | .extern SYM (boot_card) |
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| 133 | bl SYM (boot_card) /* call the first C routine */ |
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| 134 | loopstop: |
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| 135 | b loopstop |
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| 136 | |
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| 137 | /* |
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| 138 | * bssclr - zero out bss |
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| 139 | */ |
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| 140 | bssclr: |
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| 141 | lwz r4, bss_addr-base_addr(r1) /* Start of bss */ |
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| 142 | lwz r5, bss_length-base_addr(r1) /* Length of bss */ |
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| 143 | |
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| 144 | rlwinm. r5,r5,30,0x3FFFFFFF /* form length/4 */ |
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| 145 | beqlr /* no bss */ |
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| 146 | mtctr r5 /* set ctr reg */ |
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| 147 | xor r6,r6,r6 /* r6 = 0 */ |
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| 148 | clear_bss: |
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| 149 | stswi r6,r4,0x4 /* store r6 */ |
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| 150 | addi r4,r4,0x4 /* update r2 */ |
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| 151 | |
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| 152 | bdnz clear_bss /* dec counter and loop */ |
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| 153 | blr /* return */ |
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