diff options
Diffstat (limited to 'c/src/lib/libbsp/powerpc/eth_comm/start/start.S')
| -rw-r--r-- | c/src/lib/libbsp/powerpc/eth_comm/start/start.S | 154 |
1 files changed, 154 insertions, 0 deletions
diff --git a/c/src/lib/libbsp/powerpc/eth_comm/start/start.S b/c/src/lib/libbsp/powerpc/eth_comm/start/start.S new file mode 100644 index 0000000000..f7b9d420fe --- /dev/null +++ b/c/src/lib/libbsp/powerpc/eth_comm/start/start.S @@ -0,0 +1,154 @@ +/* dlentry.s + * + * $Id$ + * + * This file contains the entry veneer for RTEMS programs + * downloaded to the eth-comm board. + * + * This file was written by Jay Monkman (jmonkman@fracsa.com) + * It was based on the dlentry.s file for the Papyrus BSP, + * written by: + * + * Author: Andrew Bray <andy@i-cubed.co.uk> + * + * COPYRIGHT (c) 1995 by i-cubed ltd. + * + * To anyone who acknowledges that this file is provided "AS IS" + * without any express or implied warranty: + * permission to use, copy, modify, and distribute this file + * for any purpose is hereby granted without fee, provided that + * the above copyright notice and this notice appears in all + * copies, and that the name of i-cubed limited not be used in + * advertising or publicity pertaining to distribution of the + * software without specific, written prior permission. + * i-cubed limited makes no representations about the suitability + * of this software for any purpose. + * + */ + +#include "asm.h" + +/* + * The initial stack is set to run BELOW the code base address. + * (between the vectors and text sections) + * + * All the entry veneer has to do is to clear the BSS. + */ + +/* + * GDB likes to have debugging information for the entry veneer. + * Here is some DWARF information. + */ +/* + * There was some debugging info here, but I removed it because I + * couldn't get it to work. It isn't really necessary as far as I + * can tell. It should still be in the papyrus BSP. -Jay + */ + + + +/* + * On entry to download_entry, R3 will hold a pointer to a Board Info + * Block (boardinfo_t). This should be copied as soon as possible + * to the global M860_binfo. (The block should be copied, _NOT_ + * the pointer) + */ + + .section ".entry" /* This might have to be the first thing in the + * text section. At one time, it had to be + * first, but I don't believe it is true + * andy more. */ + PUBLIC_VAR (start) +SYM(start): + bl .startup +base_addr: + +/* + * Parameters from linker + */ +toc_pointer: + .long s.got +bss_length: + .long bss.size +bss_addr: + .long bss.start + +PUBLIC_VAR (text_addr) +text_addr: + .long text.start + +PUBLIC_VAR (text_length) +text_length: + .long text.size + + +/* + * Initialization code + */ +.startup: + /* Get start address */ + mflr r1 + + /* clear the bss section */ + bl bssclr + +/* + * Copy the Board Info Block + */ + .extern SYM(M860_binfo) + lis r6, SYM(M860_binfo)@ha + addi r6, r6, SYM(M860_binfo)@l + + lhz r4, 0(r3) /* Load the size of the block */ + rlwinm. r4, r4, 30, 0x3fffffff /* get number of words */ + + mtctr r4 + +cpy_b: lwz r5, 0(r3) /* In with the old ... */ + stw r5, 0(r6) /* ... Out with the new */ + addi r6, r6, 0x4 /* Go to the next word */ + addi r3, r3, 0x4 + bdnz cpy_b /* decrement counter and loop */ + +/* + * C_setup. + */ + + /* set toc */ + lwz r2, toc_pointer-base_addr(r1) + + /* Set up stack pointer = beginning of text section - 56 */ + addi r1, r1, -56-4 + + lis r9, 0xff00 + addi r10, 0, -16384 + sth r10, 0x950(r9) + + lis r9, 0x0000 + addi r9, r9, 0x0007 + mtspr 0x9e, r9 + + /* clear argc and argv */ + xor r3, r3, r3 + xor r4, r4, r4 + + .extern SYM (boot_card) + b SYM (boot_card) /* call the first C routine */ + +/* + * bssclr - zero out bss + */ +bssclr: + lwz r4, bss_addr-base_addr(r1) /* Start of bss */ + lwz r5, bss_length-base_addr(r1) /* Length of bss */ + + rlwinm. r5,r5,30,0x3FFFFFFF /* form length/4 */ + beqlr /* no bss */ + mtctr r5 /* set ctr reg */ + xor r6,r6,r6 /* r6 = 0 */ +clear_bss: + stswi r6,r4,0x4 /* store r6 */ + addi r4,r4,0x4 /* update r2 */ + + bdnz clear_bss /* dec counter and loop */ + blr /* return */ |