srt0.S revision 1.1.2.2
1 1.1.2.2 nathanw /* $NetBSD: srt0.S,v 1.1.2.2 2002/02/28 04:11:12 nathanw Exp $ */ 2 1.1.2.2 nathanw 3 1.1.2.2 nathanw /*- 4 1.1.2.2 nathanw * Copyright (c) 2002 The NetBSD Foundation, Inc. 5 1.1.2.2 nathanw * All rights reserved. 6 1.1.2.2 nathanw * 7 1.1.2.2 nathanw * This code is derived from software contributed to The NetBSD Foundation 8 1.1.2.2 nathanw * by Steve C. Woodford. 9 1.1.2.2 nathanw * 10 1.1.2.2 nathanw * Redistribution and use in source and binary forms, with or without 11 1.1.2.2 nathanw * modification, are permitted provided that the following conditions 12 1.1.2.2 nathanw * are met: 13 1.1.2.2 nathanw * 1. Redistributions of source code must retain the above copyright 14 1.1.2.2 nathanw * notice, this list of conditions and the following disclaimer. 15 1.1.2.2 nathanw * 2. Redistributions in binary form must reproduce the above copyright 16 1.1.2.2 nathanw * notice, this list of conditions and the following disclaimer in the 17 1.1.2.2 nathanw * documentation and/or other materials provided with the distribution. 18 1.1.2.2 nathanw * 3. All advertising materials mentioning features or use of this software 19 1.1.2.2 nathanw * must display the following acknowledgement: 20 1.1.2.2 nathanw * This product includes software developed by the NetBSD 21 1.1.2.2 nathanw * Foundation, Inc. and its contributors. 22 1.1.2.2 nathanw * 4. Neither the name of The NetBSD Foundation nor the names of its 23 1.1.2.2 nathanw * contributors may be used to endorse or promote products derived 24 1.1.2.2 nathanw * from this software without specific prior written permission. 25 1.1.2.2 nathanw * 26 1.1.2.2 nathanw * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 27 1.1.2.2 nathanw * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 1.1.2.2 nathanw * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 29 1.1.2.2 nathanw * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 30 1.1.2.2 nathanw * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 1.1.2.2 nathanw * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 1.1.2.2 nathanw * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 1.1.2.2 nathanw * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 1.1.2.2 nathanw * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 1.1.2.2 nathanw * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 1.1.2.2 nathanw * POSSIBILITY OF SUCH DAMAGE. 37 1.1.2.2 nathanw */ 38 1.1.2.2 nathanw 39 1.1.2.2 nathanw #include <machine/asm.h> 40 1.1.2.2 nathanw #include <machine/psl.h> 41 1.1.2.2 nathanw #include <powerpc/spr.h> 42 1.1.2.2 nathanw 43 1.1.2.2 nathanw #define STACK_SIZE 8192 44 1.1.2.2 nathanw 45 1.1.2.2 nathanw /* 46 1.1.2.2 nathanw * The main entry point when loaded by PPC-Bug. 47 1.1.2.2 nathanw * 48 1.1.2.2 nathanw * There are two possible entry conditions here: 49 1.1.2.2 nathanw * 50 1.1.2.2 nathanw * 1) We were booted in `PReP' mode, either from disk or the network. 51 1.1.2.2 nathanw * In this case, we have no control over the load address so we 52 1.1.2.2 nathanw * have to relocate ourselves to the appropriate place. 53 1.1.2.2 nathanw * The firmware passes us the following registers: 54 1.1.2.2 nathanw * 55 1.1.2.2 nathanw * r1 -> Temporary stack 56 1.1.2.2 nathanw * r3 -> Residual Data 57 1.1.2.2 nathanw * r4 -> The address we were loaded to 58 1.1.2.2 nathanw * r5 -> Zero 59 1.1.2.2 nathanw * 60 1.1.2.2 nathanw * 2) We were booted over the network in Non-PReP mode. In this case, 61 1.1.2.2 nathanw * the load address is usually set using PPC-Bug's "niot" command, 62 1.1.2.2 nathanw * but we won't depend on it so relocation may be required. The 63 1.1.2.2 nathanw * firmware passes us the following registers: 64 1.1.2.2 nathanw * 65 1.1.2.2 nathanw * r1 -> Temporary stack 66 1.1.2.2 nathanw * r3 -> CLUN of the network device we booted from 67 1.1.2.2 nathanw * r4 -> DLUN of the network device we booted from 68 1.1.2.2 nathanw * r5 -> Non-zero 69 1.1.2.2 nathanw * r6 -> Base address of network device 70 1.1.2.2 nathanw * r7 -> Execution address of loaded program 71 1.1.2.2 nathanw * r8 -> Address of IP-address data structure 72 1.1.2.2 nathanw * r9 -> Pointer to start of filename string 73 1.1.2.2 nathanw * r10 -> Pointer to end+1 of filename string 74 1.1.2.2 nathanw * r11 -> Pointer to start of argument string 75 1.1.2.2 nathanw * r12 -> Pointer to end+1 of argument string 76 1.1.2.2 nathanw * 77 1.1.2.2 nathanw * The obvious way to distinguish between the two boot modes is by 78 1.1.2.2 nathanw * checking the value of r5. 79 1.1.2.2 nathanw */ 80 1.1.2.2 nathanw ENTRY(_start) 81 1.1.2.2 nathanw bl 1f 82 1.1.2.2 nathanw 1: xor r0,r0,r0 83 1.1.2.2 nathanw 84 1.1.2.2 nathanw /* First, switch off Instruction and Data caches. */ 85 1.1.2.2 nathanw mfspr r13,SPR_HID0 86 1.1.2.2 nathanw LDCONST(r14, HID0_DCE|HID0_ICE) 87 1.1.2.2 nathanw andc r13,r13,r14 88 1.1.2.2 nathanw sync 89 1.1.2.2 nathanw mtspr SPR_HID0,r13 90 1.1.2.2 nathanw 91 1.1.2.2 nathanw 92 1.1.2.2 nathanw /* 93 1.1.2.2 nathanw * All registers now available. Let's see if we need to relocate 94 1.1.2.2 nathanw */ 95 1.1.2.2 nathanw LDCONST(r13,_C_LABEL(_start)) /* Where we'd like to be */ 96 1.1.2.2 nathanw LDCONST(r14,_C_LABEL(edata)) /* End of data section */ 97 1.1.2.2 nathanw LDCONST(r15,0x3) 98 1.1.2.2 nathanw add r14,r14,r15 99 1.1.2.2 nathanw andc r14,r14,r15 /* Rounded up to the nearest 32-bits */ 100 1.1.2.2 nathanw sub r15,r14,r13 /* Our size, in bytes */ 101 1.1.2.2 nathanw mflr r16 /* Get address we were loaded to */ 102 1.1.2.2 nathanw subi r16,r16,0x4 /* Correct for branch */ 103 1.1.2.2 nathanw cmp cr0,r13,r16 /* Do we need to relocate? */ 104 1.1.2.2 nathanw beq _ASM_LABEL(clrbss) /* No relocation necessary */ 105 1.1.2.2 nathanw li r17,0x4 106 1.1.2.2 nathanw bgt 1f /* Relocate using forward copy? */ 107 1.1.2.2 nathanw 108 1.1.2.2 nathanw /* Nope. Need to copy in reverse in case of overlap */ 109 1.1.2.2 nathanw mr r13,r14 /* dest -> end */ 110 1.1.2.2 nathanw add r16,r16,r15 /* src + size */ 111 1.1.2.2 nathanw subi r17,r17,0x8 /* Increment is -4 */ 112 1.1.2.2 nathanw 113 1.1.2.2 nathanw /* 114 1.1.2.2 nathanw * Do the relocation 115 1.1.2.2 nathanw * r13 -> dest 116 1.1.2.2 nathanw * r15 -> number of bytes 117 1.1.2.2 nathanw * r16 -> src 118 1.1.2.2 nathanw * r17 -> Increment (+4 or -4) 119 1.1.2.2 nathanw */ 120 1.1.2.2 nathanw 1: srwi r15,r15,0x2 /* Convert length to 32-bit words */ 121 1.1.2.2 nathanw mtctr r15 /* Save in counter register */ 122 1.1.2.2 nathanw 123 1.1.2.2 nathanw 2: lwz r15,0(r16) 124 1.1.2.2 nathanw stw r15,0(r13) 125 1.1.2.2 nathanw add r16,r16,r17 126 1.1.2.2 nathanw add r13,r13,r17 127 1.1.2.2 nathanw bdnz 2b 128 1.1.2.2 nathanw 129 1.1.2.2 nathanw /* Now do an absolute jump to the relocated code */ 130 1.1.2.2 nathanw LDCONST(r13,_ASM_LABEL(clrbss)) 131 1.1.2.2 nathanw mtlr r13 132 1.1.2.2 nathanw blr 133 1.1.2.2 nathanw 134 1.1.2.2 nathanw ASENTRY(clrbss) 135 1.1.2.2 nathanw LDCONST(r13,_C_LABEL(edata)) /* End of the data section */ 136 1.1.2.2 nathanw LDCONST(r14,_C_LABEL(end)) /* End of BSS */ 137 1.1.2.2 nathanw LDCONST(r15,0x3) 138 1.1.2.2 nathanw add r14,r14,r15 139 1.1.2.2 nathanw andc r14,r14,r15 /* Round-up end of BSS to 32-bits */ 140 1.1.2.2 nathanw sub r15,r14,r13 /* r15 == length of BSS */ 141 1.1.2.2 nathanw srwi r15,r15,0x2 142 1.1.2.2 nathanw mtctr r15 /* CTR == # of 32-bit words in BSS */ 143 1.1.2.2 nathanw 1: stw r0,0(r13) /* Clear BSS */ 144 1.1.2.2 nathanw addi r13,r13,4 145 1.1.2.2 nathanw bdnz 1b 146 1.1.2.2 nathanw 147 1.1.2.2 nathanw /* Fix up our own stack */ 148 1.1.2.2 nathanw LDCONST(r1,stack) 149 1.1.2.2 nathanw addi r1,r1,STACK_SIZE-0x10 150 1.1.2.2 nathanw LDCONST(r13,0x0f) 151 1.1.2.2 nathanw andc r1,r1,r13 152 1.1.2.2 nathanw 153 1.1.2.2 nathanw /* 154 1.1.2.2 nathanw * Copy the arguments passed in from Bug into bug_bootinfo 155 1.1.2.2 nathanw * 156 1.1.2.2 nathanw * See bugsyscalls.h for details. 157 1.1.2.2 nathanw */ 158 1.1.2.2 nathanw LDCONST(r13,_C_LABEL(bug_bootinfo)) 159 1.1.2.2 nathanw stw r5,0x00(r13) 160 1.1.2.2 nathanw stw r3,0x04(r13) 161 1.1.2.2 nathanw stw r4,0x08(r13) 162 1.1.2.2 nathanw stw r6,0x0c(r13) 163 1.1.2.2 nathanw stw r7,0x10(r13) 164 1.1.2.2 nathanw stw r8,0x14(r13) 165 1.1.2.2 nathanw stw r9,0x18(r13) 166 1.1.2.2 nathanw stw r10,0x1c(r13) 167 1.1.2.2 nathanw stw r11,0x20(r13) 168 1.1.2.2 nathanw stw r12,0x24(r13) 169 1.1.2.2 nathanw 170 1.1.2.2 nathanw mr r3,r13 171 1.1.2.2 nathanw bl _C_LABEL(main) /* void main(void) */ 172 1.1.2.2 nathanw /* FALLTHROUGH */ 173 1.1.2.2 nathanw 174 1.1.2.2 nathanw /* 175 1.1.2.2 nathanw * Return to the debugger, either because main() returned or via panic(). 176 1.1.2.2 nathanw */ 177 1.1.2.2 nathanw ENTRY(_rtt) 178 1.1.2.2 nathanw addi r10,0,0x0063 179 1.1.2.2 nathanw sc 180 1.1.2.2 nathanw 1: nop 181 1.1.2.2 nathanw b 1b 182 1.1.2.2 nathanw 183 1.1.2.2 nathanw /* 184 1.1.2.2 nathanw * C code runs on this stack. 185 1.1.2.2 nathanw */ 186 1.1.2.2 nathanw .comm stack,STACK_SIZE,4 187 1.1.2.2 nathanw .comm errno,4,4 188 1.1.2.2 nathanw .comm debug,4,4 189
Indexes created Wed Oct 29 20:09:47 GMT 2025