📄 ofwboot.s
字号:
.section .text
.globl setup_bats
_start:
.long 0xe00000 + 12
.long 0
.long 0
_begin:
sync
isync
lis %r1,stack@ha
addi %r1,%r1,stack@l
addi %r1,%r1,16384 - 0x10
mfmsr %r8
li %r0,0
mtmsr %r0
isync
bl setup_bats
li %r8,0x3030
mtmsr %r8
/* Store ofw call addr */
mr %r21,%r5
lis %r10,0xe00000@ha
stw %r5,ofw_call_addr - _start@l(%r10)
lis %r4,_binary_freeldr_tmp_end@ha
addi %r4,%r4,_binary_freeldr_tmp_end@l
lis %r3,_binary_freeldr_tmp_start@ha
addi %r3,%r3,_binary_freeldr_tmp_start@l
lis %r5,0x8000@ha
addi %r5,%r5,0x8000@l
bl copy_bits
bl zero_registers
lis %r3,0xe00000@ha
addi %r3,%r3,freeldr_banner - _start
bl ofw_print_string
bl ofw_print_eol
bl setup_exc
/* Zero CTR */
mtcr %r31
lis %r3,0x8000@ha
addi %r3,%r3,0x8000@l
mtlr %r3
lis %r3,call_ofw@ha
addi %r3,%r3,call_ofw - _start
b call_freeldr
/*
* lifted from ppc/boot/openfirmware/misc.S
* Copyright (C) Paul Mackerras 1997.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation ; either version
* 2 of the License, or (at your option) any later version.
*/
/*
* Use the BAT2 & 3 registers to map the 1st 16MB of RAM to
* the address given as the 1st argument.
*/
setup_bats:
mfpvr 5
rlwinm 5,5,16,16,31 /* r3 = 1 for 601, 4 for 604 */
cmpwi 0,5,1
li 0,0
bne 4f
mtibatl 3,0 /* invalidate BAT first */
ori 3,3,4 /* set up BAT registers for 601 */
li 4,0x7f
mtibatu 2,3
mtibatl 2,4
oris 3,3,0x80
oris 4,4,0x80
mtibatu 3,3
mtibatl 3,4
b 5f
4: mtdbatu 3,0 /* invalidate BATs first */
mtibatu 3,0
ori 3,3,0xff /* set up BAT registers for 604 */
li 4,2
mtdbatl 2,4
mtdbatu 2,3
mtibatl 2,4
mtibatu 2,3
oris 3,3,0x80
oris 4,4,0x80
mtdbatl 3,4
mtdbatu 3,3
mtibatl 3,4
mtibatu 3,3
5: sync
isync
blr
.align 4
call_freeldr:
/* Get the address of the functions list --
* Note:
* Because of little endian switch we must use an even number of
* instructions here.. Pad with a nop if needed. */
mfmsr %r10
ori %r10,%r10,1
mtmsr %r10
nop
/* Note that this is little-endian from here on */
blr
nop
.align 4
call_ofw:
/* R3 has the function offset to call (n * 4)
* Other arg registers are unchanged.
* Note that these 4 instructions are in reverse order due to
* little-endian convention */
andi. %r0,%r0,65534
mfmsr %r0
mtmsr %r0
/* Now normal ordering resumes */
subi %r1,%r1,0x100
stw %r8,4(%r1)
stw %r9,8(%r1)
stw %r10,12(%r1)
mflr %r8
stw %r8,16(%r1)
lis %r10,0xe00000@ha
add %r9,%r3,%r10
lwz %r3,ofw_functions - _start@l(%r9)
mtctr %r3
mr %r3,%r4
mr %r4,%r5
mr %r5,%r6
mr %r6,%r7
mr %r7,%r8
/* Goto the swapped function */
bctrl
lwz %r8,16(%r1)
mtlr %r8
lwz %r8,4(%r1)
lwz %r9,8(%r1)
lwz %r10,12(%r1)
addi %r1,%r1,0x100
/* Ok, go back to little endian */
mfmsr %r0
ori %r0,%r0,1
mtmsr %r0
/* Note that this is little-endian from here on */
blr
nop
zero_registers:
xor %r2,%r2,%r2
mr %r0,%r2
mr %r3,%r2
mr %r4,%r2
mr %r5,%r2
mr %r6,%r2
mr %r7,%r2
mr %r8,%r2
mr %r9,%r2
mr %r10,%r2
mr %r11,%r2
mr %r12,%r2
mr %r13,%r2
mr %r14,%r2
mr %r15,%r2
mr %r12,%r2
mr %r13,%r2
mr %r14,%r2
mr %r15,%r2
mr %r16,%r2
mr %r17,%r2
mr %r18,%r2
mr %r19,%r2
mr %r20,%r2
mr %r21,%r2
mr %r22,%r2
mr %r23,%r2
mr %r24,%r2
mr %r25,%r2
mr %r26,%r2
mr %r27,%r2
mr %r28,%r2
mr %r29,%r2
mr %r30,%r2
mr %r31,%r2
blr
prim_strlen:
mr %r5,%r3
prim_strlen_loop:
lbz %r4,0(%r3)
cmpi 0,0,%r4,0
beq prim_strlen_done
addi %r3,%r3,1
b prim_strlen_loop
prim_strlen_done:
sub %r3,%r3,%r5
blr
copy_bits:
cmp 0,0,%r3,%r4
beqlr
lwz %r6,0(%r3)
stw %r6,0(%r5)
addi %r3,%r3,4
addi %r5,%r5,4
b copy_bits
ofw_print_string_hook:
bl ofw_print_number
bl ofw_exit
ofw_print_string:
/* Reserve some stack space */
subi %r1,%r1,32
/* Save args */
stw %r3,0(%r1)
/* Save the lr, a scratch register */
stw %r8,8(%r1)
mflr %r8
stw %r8,12(%r1)
/* Load the package name */
lis %r3,0xe00000@ha
addi %r3,%r3,ofw_chosen_name - _start
/* Fire */
bl ofw_finddevice
/* Load up for getprop */
stw %r3,16(%r1)
lis %r4,0xe00000@ha
addi %r4,%r4,ofw_stdout_name - _start
addi %r5,%r1,20
li %r6,4
bl ofw_getprop
/* Measure the string and remember the length */
lwz %r3,0(%r1)
bl prim_strlen
mr %r5,%r3
lwz %r3,20(%r1)
lwz %r4,0(%r1)
/* Write the string */
bl ofw_write
/* Return */
lwz %r8,12(%r1)
mtlr %r8
lwz %r8,8(%r1)
addi %r1,%r1,32
blr
/* Print 8 hex digits representing a number in r3 */
ofw_print_number:
subi %r1,%r1,32
stw %r8,0(%r1)
mflr %r8
stw %r8,4(%r1)
stw %r9,8(%r1)
xor %r9,%r9,%r9
stw %r9,12(%r1)
/* Set up and, devide, shift */
mr %r8,%r3
lis %r6,0xf0000000@ha
lis %r7,0x10000000@ha
li %r9,8
ofw_number_loop:
nop
cmpi 0,0,%r9,0
beq ofw_number_return
subi %r9,%r9,1
/* Body: isolate digit, divide, print */
and %r5,%r6,%r8
divwu %r4,%r5,%r7
srwi %r6,%r6,4
srwi %r7,%r7,4
nop
cmpi 0,0,%r4,10
bge ofw_number_letter
addi %r4,%r4,'0'
b ofw_number_digit_out
ofw_number_letter:
addi %r4,%r4,'A' - 10
ofw_number_digit_out:
stb %r4,12(%r1)
addi %r3,%r1,12
stw %r6,16(%r1)
stw %r7,20(%r1)
stw %r8,24(%r1)
stw %r9,28(%r1)
bl ofw_print_string
lwz %r6,16(%r1)
lwz %r7,20(%r1)
lwz %r8,24(%r1)
lwz %r9,28(%r1)
b ofw_number_loop
ofw_number_return:
/* Return */
lwz %r9,8(%r1)
lwz %r8,4(%r1)
mtlr %r8
lwz %r8,0(%r1)
addi %r1,%r1,32
blr
ofw_print_eol:
subi %r1,%r1,16
stw %r8,0(%r1)
mflr %r8
stw %r8,4(%r1)
li %r4,0x0d0a
sth %r4,8(%r1)
xor %r4,%r4,%r4
sth %r4,10(%r1)
addi %r3,%r1,8
bl ofw_print_string
lwz %r8,4(%r1)
mtlr %r8
lwz %r8,0(%r1)
addi %r1,%r1,16
blr
ofw_print_nothing:
subi %r1,%r1,16
stw %r8,0(%r1)
mflr %r8
stw %r8,4(%r1)
li %r4,0
sth %r4,8(%r1)
xor %r4,%r4,%r4
sth %r4,10(%r1)
addi %r3,%r1,8
bl ofw_print_string
lwz %r8,4(%r1)
mtlr %r8
lwz %r8,0(%r1)
addi %r1,%r1,16
blr
ofw_print_space:
subi %r1,%r1,16
stw %r8,0(%r1)
mflr %r8
stw %r8,4(%r1)
li %r4,0x2000
sth %r4,8(%r1)
xor %r4,%r4,%r4
sth %r4,10(%r1)
addi %r3,%r1,8
bl ofw_print_string
lwz %r8,4(%r1)
mtlr %r8
lwz %r8,0(%r1)
addi %r1,%r1,16
blr
ofw_print_regs:
/* Construct ofw exit call */
subi %r1,%r1,0xa0
stw %r0,0(%r1)
stw %r1,4(%r1)
stw %r2,8(%r1)
stw %r3,12(%r1)
stw %r4,16(%r1)
stw %r5,20(%r1)
stw %r6,24(%r1)
stw %r7,28(%r1)
stw %r8,32(%r1)
stw %r9,36(%r1)
stw %r10,40(%r1)
stw %r11,44(%r1)
stw %r12,48(%r1)
stw %r13,52(%r1)
stw %r14,56(%r1)
stw %r15,60(%r1)
stw %r16,64(%r1)
stw %r17,68(%r1)
stw %r18,72(%r1)
stw %r19,76(%r1)
stw %r20,80(%r1)
stw %r21,84(%r1)
stw %r22,88(%r1)
stw %r23,92(%r1)
stw %r24,96(%r1)
stw %r25,100(%r1)
stw %r26,104(%r1)
stw %r27,108(%r1)
stw %r28,112(%r1)
stw %r29,116(%r1)
stw %r30,120(%r1)
stw %r31,124(%r1)
mflr %r0
stw %r0,128(%r1)
mfcr %r0
stw %r0,132(%r1)
mfctr %r0
stw %r0,136(%r1)
mfmsr %r0
stw %r0,140(%r1)
/* Count at zero */
xor %r0,%r0,%r0
stw %r0,144(%r1)
mr %r3,%r1
stw %r3,148(%r1)
/* Body, print the regname, then the register */
ofw_register_loop:
lwz %r3,144(%r1)
cmpi 0,0,%r3,32
beq ofw_register_special
lis %r3,0xe00000@ha
addi %r3,%r3,freeldr_reg_init - _start
bl ofw_print_string
lwz %r3,144(%r1)
bl ofw_print_number
bl ofw_print_space
lwz %r3,144(%r1)
mulli %r3,%r3,4
add %r3,%r1,%r3
lwz %r3,0(%r3)
stw %r3,152(%r1)
bl ofw_print_number
lwz %r3,144(%r1)
addi %r3,%r3,1
stw %r3,144(%r1)
b done_dump
dump_optional:
bl ofw_print_space
bl ofw_print_space
lwz %r3,152(%r1)
lwz %r3,0(%r3)
bl ofw_print_number
bl ofw_print_space
lwz %r3,152(%r1)
lwz %r3,4(%r3)
bl ofw_print_number
bl ofw_print_space
lwz %r3,152(%r1)
lwz %r3,8(%r3)
bl ofw_print_number
bl ofw_print_space
lwz %r3,152(%r1)
lwz %r3,12(%r3)
bl ofw_print_number
bl ofw_print_space
done_dump:
bl ofw_print_eol
b ofw_register_loop
ofw_register_special:
/* LR */
lis %r3,0xe00000@ha
addi %r3,%r3,freeldr_reg_lr - _start
bl ofw_print_string
bl ofw_print_space
lwz %r3,128(%r1)
bl ofw_print_number
bl ofw_print_eol
/* CR */
lis %r3,0xe00000@ha
addi %r3,%r3,freeldr_reg_cr - _start
bl ofw_print_string
bl ofw_print_space
lwz %r3,132(%r1)
bl ofw_print_number
bl ofw_print_eol
/* CTR */
lis %r3,0xe00000@ha
addi %r3,%r3,freeldr_reg_ctr - _start
bl ofw_print_string
bl ofw_print_space
lwz %r3,136(%r1)
bl ofw_print_number
bl ofw_print_eol
/* MSR */
lis %r3,0xe00000@ha
addi %r3,%r3,freeldr_reg_msr - _start
bl ofw_print_string
bl ofw_print_space
lwz %r3,140(%r1)
bl ofw_print_number
bl ofw_print_eol
/* Return */
lwz %r0,128(%r1)
mtlr %r0
lwz %r0,0(%r1)
lwz %r2,8(%r1)
lwz %r3,12(%r1)
lwz %r4,16(%r1)
lwz %r5,20(%r1)
lwz %r6,24(%r1)
lwz %r7,28(%r1)
addi %r1,%r1,0xa0
blr
ofw_finddevice_hook:
subi %r1,%r1,32
stw %r3,0(%r1)
mflr %r3
stw %r3,4(%r1)
lwz %r3,0(%r1)
bl ofw_finddevice
stw %r3,0(%r1)
lwz %r3,4(%r1)
mtlr %r3
lwz %r3,0(%r1)
addi %r1,%r1,32
blr
ofw_finddevice:
/* Reserve stack space ...
* 20 bytes for the ofw call,
* r8, r9, and lr */
subi %r1,%r1,32
/* Store r8, r9, lr */
stw %r8,20(%r1)
stw %r9,24(%r1)
mflr %r8
stw %r8,28(%r1)
/* Get finddevice name */
lis %r8,0xe00000@ha
addi %r9,%r8,ofw_finddevice_name - _start
stw %r9,0(%r1)
/* 1 Argument and 1 return */
li %r9,1
stw %r9,4(%r1)
stw %r9,8(%r1)
stw %r3,12(%r1)
/* Load up the call address */
lwz %r9,ofw_call_addr - _start(%r8)
mtlr %r9
/* Set argument */
mr %r3,%r1
/* Fire */
blrl
⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -