crt0.lst

au1200下的boot代码

GAS LISTING /tmp/ccZtg9Qb.s 			page 1


   1              	# 1 "/mnt/hgfs/boot/booter/source/crt0.S"
   2              	# 1 "/mnt/hgfs/boot/booter/source//"
   1              	#
   1              	...
   0              	
   0              	
   2              	# Low-level startup code for C programs.
   3              	# Also provides alot of common low-level utilities
   4              	# to facilitate C code.
   5              	#
   6              	
   7              	#define zero	$0
   8              	#define v0		$2
   9              	#define v1		$3
  10              	#define a0		$4
  11              	#define a1		$5
  12              	#define a2		$6
  13              	#define a3		$7
  14              	#define t0		$8
  15              	#define t1		$9
  16              	#define t2		$10
  17              	#define t3		$11
  18              	#define t4		$12
  19              	#define t5		$13
  20              	#define t6		$14
  21              	#define t7		$15
  22              	#define s0		$16
  23              	#define s1		$17
  24              	#define s2		$18
  25              	#define s3		$19
  26              	#define s4		$20
  27              	#define s5		$21
  28              	#define s6		$22
  29              	#define s7		$23
  30              	#define t8		$24
  31              	#define t9		$25
  32              	#define k0		$26
  33              	#define k1		$27
  34              	#define gp		$28
  35              	#define sp		$29
  36              	#define fp		$30
  37              	#define s8		$30
  38              	#define ra		$31
  39              	
  40              	#define CP0_Index		$0
  41              	#define CP0_Random		$1
  42              	#define CP0_EntryLo0	$2
  43              	#define CP0_EntryLo1	$3
  44              	#define CP0_Context		$4
  45              	#define CP0_PageMask	$5
  46              	#define CP0_Wired		$6
  47              	#define CP0_BadVAddr	$8
  48              	#define CP0_Count		$9
  49              	#define CP0_EntryHi		$10
  50              	#define CP0_Compare		$11
  51              	#define CP0_Status		$12
  52              	#define CP0_Cause		$13
GAS LISTING /tmp/ccZtg9Qb.s 			page 2


  53              	#define CP0_EPC			$14
  54              	#define CP0_PRId		$15
  55              	#define CP0_Config		$16
  56              	#define CP0_Config0		$16
  57              	#define CP0_Config1		$16,1
  58              	#define CP0_LLAddr		$17
  59              	#define CP0_WatchLo		$18
  60              	#define CP0_IWatchLo	$18,1
  61              	#define CP0_WatchHi		$19
  62              	#define CP0_IWatchHi	$19,1
  63              	#define CP0_Scratch		$22
  64              	#define CP0_Debug		$23
  65              	#define CP0_DEPC		$24
  66              	#define CP0_PerfCnt		$25
  67              	#define CP0_PerfCtrl	$25,1
  68              	#define CP0_DTag		$28
  69              	#define CP0_DData		$28,1
  70              	#define CP0_ITag		$29
  71              	#define CP0_IData		$29,1
  72              	#define CP0_ErrorEPC	$30
  73              	#define CP0_DESave		$31
  74              	
  75              		.section ".init"
  76              		.text
  77              			.extern	main
  78              			.extern commonInit
  79              			.extern platformInit
  80              			.extern startupStackFrame
  81              	
  82              	
  83              			.global	start
  84              	start:
  85              			#
  86              			# Save SP for exitToYamon()
  87              			#
  88              			
  89 0000 0000083C 			la		t0,startupStackFrame
  89      00000825 
  90 0008 00001DAD 			sw		sp,0(t0)
  91              	
  92              			#
  93              			# Initialize Stack Pointer
  94              			#
  95 000c 00001D3C 			la		sp,__stacktop
  95      0000BD27 
  96              	
  97 0014 E8FFBD27 			addiu		sp,sp,-24
  98              	
  99              			# Preserve a0,a1,a2,a3 from YAMON (argc, argv, envp)
 100 0018 0000A4AF 			sw		a0,0(sp)
 101 001c 0400A5AF 			sw		a1,4(sp)
 102 0020 0800A6AF 			sw		a2,8(sp)
 103 0024 0C00A7AF 			sw		a3,12(sp)
 104              			# Preserve return address into YAMON
 105 0028 1000BFAF 			sw		ra,16(sp)
 106              	
 107              			#
GAS LISTING /tmp/ccZtg9Qb.s 			page 3


 108              			# Initialize GP (needed by prebuilt libs)
 109              			#
 110 002c 00001C3C 			la		gp,_gp
 110      00009C27 
 111              	
 112              	
 113              			/* turn off mem_stcfg0[PM], it interferes */
 114              	/*commented by shuaiwen for sdram running
 115              			li		t2,0xB4001000
 116              			lw		t0,0(t2)
 117              			li		t1,~0x00000010
 118              			and		t0,t0,t1
 119              			sw		t0,0(t2)
 120              			sync
 121              	shuaiwen comment ended*/
 122              			/* Execute From Cachable Space */
 123              			/*shuaiwen comment begian
 124              			la		t0, executeCache
 125              			jr		t0
 126              			nop
 127              		executeCache:
 128              	shuaiwen comment ended
 129              	*/
 130              			#
 131              			# zero out bss
 132              			#
 133 0034 0000000C 			jal		initialize_bss 
 133      00000000 
 134 003c 00000000 			nop
 135              	
 136              			#
 137              			# Copy data segment if it needs to be relocated
 138              			#
 139 0040 0000000C 			jal		copy_data_segment 
 139      00000000 
 140 0048 00000000 			nop
 141              	
 142              			#
 143              			# Initialize infrastructure
 144              			#
 145              			#jal		commonInit  comment by shuaiwen
 146 004c 00000000 			nop
 147 0050 0000000C 			jal		platformInit
 147      00000000 
 148 0058 00000000 			nop
 149              	
 150              			# Restore a0,a1,a2,a3 from YAMON for args to main()
 151 005c 0000A48F 			lw		a0,0(sp)
 152 0060 0400A58F 			lw		a1,4(sp)
 153 0064 0800A68F 			lw		a2,8(sp)
 154 0068 0C00A78F 			lw		a3,12(sp)
 155              	
 156              			# Call c main()
 157 006c 0000000C 			jal		main
 157      00000000 
 158 0074 00000000 			nop
 159              	
GAS LISTING /tmp/ccZtg9Qb.s 			page 4


 160              			.global exitToYamon
 161              	exitToYamon:
 162              			# Pause 0.5 second to allow UART queues to drain
 163 0078 F4010424 			li		a0, 500
 164 007c 0000000C 			jal		msdelay
 164      00000000 
 165 0084 00000000 			nop
 166              	
 167              			# Restore return address into YAMON
 168 0088 1000BF8F 			lw		ra,16(sp)
 169              	
 170              			# Restore YAMON stack frame
 171 008c 0000083C 			la		t0,startupStackFrame
 171      00000825 
 172 0094 00001D8D 			lw		sp,0(t0)
 173              	
 174              			# Return to YAMON
 175 0098 0800E003 			jr		ra
 175      00000000 
 176 00a0 00000000 			nop
 177              	
 178              			#
 179              			# GCC 2.95.3 automatically calls __gccmain() from main()
 180              			# GCC 3.0.1 automatically calls __main() from main()
 181              			#
 182              			.global	__gccmain
 183              			.global __main
 184              	__gccmain:
 185              	__main:
 186 00a4 0800E003 			jr		ra
 186      00000000 
 187 00ac 00000000 			nop
 188              	
 189              	########################################################################
 190              	
 191              	
 192              			.text
 193              	/*
 194              	 * Cache flush and invalidate routines
 195              	 */
 196              		.global icacheFlush
 197              	icacheFlush:
 198 00b0 00400824 		li	t0,(16*1024)
 199 00b4 20000924 		li	t1,32
 200 00b8 00800A3C 		li	t2,0x80000000
 201 00bc 21580A01 		addu	t3,t0,t2
 202              	iloop:
 203 00c0 000040BD 		cache	0,0(t2)
 204 00c4 21504901 		addu	t2,t1
 205 00c8 FDFF4B15 		bne	t2,t3,iloop
 205      00000000 
 206 00d0 00000000 		nop
 207 00d4 0800E003 		jr	ra
 207      00000000 
 208 00dc 00000000 		nop
 209              	
 210              		.global dcacheFlush
GAS LISTING /tmp/ccZtg9Qb.s 			page 5


 211              	dcacheFlush:
 212 00e0 00400824 		li	t0,(16*1024)
 213 00e4 20000924 		li	t1,32
 214 00e8 00800A3C 		li	t2,0x80000000
 215 00ec 21580A01 		addu	t3,t0,t2
 216              	dloop:
 217 00f0 000041BD 		cache	1,0(t2)
 218 00f4 21504901 		addu	t2,t1
 219 00f8 FDFF4B15 		bne	t2,t3,dloop
 219      00000000 
 220 0100 00000000 		nop
 221 0104 0800E003 		jr	ra
 221      00000000 
 222 010c 00000000 		nop
 223              	
 224              	########################################################################
 225              	/*
 226              	 * Cache flush and invalidate routines for fixed range
 227              	 */
 228              		/*
 229              	 	 * a0 -> buffer start address.
 230              		 * a1 -> length/range to be flushed/invalidated.
 231              		 */
 232              		.global dcacheFlushInvalidateRange
 233              	dcacheFlushInvalidateRange:
 234 0110 2148A400 		addu	t1,a1,a0		# end of range
 235              	dfiloop:
 236 0114 000095BC 		cache	0x15,0(a0)		# wb inv address
 237 0118 20008424 		addiu	a0,32			# cache line size
 238 011c 2B088900 		bltu	a0,t1,dfiloop		# loop if not end of range
 238      FCFF2014 
 238      00000000 
 239 0128 00000000 		nop
 240 012c 0800E003 		jr	ra
 240      00000000 
 241 0134 00000000 		nop
 242              	
 243              	
 244              		/*
 245              	 	 * a0 -> buffer start address, must be cache line aligned.
 246              		 * a1 -> length/range to be invalidated.
 247              		 */
 248              		.global dcacheInvalidateRange
 249              	dcacheInvalidateRange:
 250 0138 2148A400 		addu	t1,a1,a0		# end of range
 251              	diloop:
 252 013c 000091BC 		cache	0x11,0(a0)		# inv address
 253 0140 20008424 		addiu	a0,32			# cache line size
 254 0144 2B088900 		bltu	a0,t1,diloop		# loop if not end of range
 254      FCFF2014 
 254      00000000 
 255 0150 00000000 		nop
 256 0154 0800E003 		jr	ra
 256      00000000 
 257 015c 00000000 		nop
 258              	
 259              	
GAS LISTING /tmp/ccZtg9Qb.s 			page 6


 260              	
 261              	########################################################################
 262              	#if 0
 263              		/*
 264              		 * # of loops passed in A0
 265              		 * ptr to start counter passed in A1
 266              		 * ptr to stop counter passed in A2
 267              		 * start Counter passed out in V0
 268              		 * end Counter passed out in V1
 269              		 */
 270              		.global maddloop
 271              	maddloop:
 272              		.set noreorder
 273              		mthi	zero
 274              		mtlo	zero
 275              		li	t0, 1
 276              		mfc0	t1, CP0_Count
 277              		sw	t1, 0(a1)
 278              	ml:
 279              		madd	t0, a0
 280              		#madd	t0, a0
 281              		#madd	t0, a0
 282              		bne	zero, a0, ml
 283              		addiu	a0, -1
 284              		mfc0	t1, CP0_Count
 285              		sw	t1, 0(a2)
 286              		j	ra
 287              		nop
 288              		.set reorder
 289              	#endif
 290              	
 291              	########################################################################
 292              	
 293              		/* t1 has chip-select sdaddr value */
 294              		/* it updates v0 accordingly */