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Line 41... Line 41...
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.global tlb_refill_entry
 41 
.global tlb_refill_entry
42 
.global cache_error_entry
 42 
.global cache_error_entry
43 
.global exception_entry
 43 
.global exception_entry
44 
.global userspace_asm
 44 
.global userspace_asm
45 
 
 45 
 
- 
 
 46 
# Which status bits should are thread-local
- 
 
 47 
#define REG_SAVE_MASK 0x1f # KSU(UM), EXL, ERL, IE
- 
 
 48
46 
# Save registers to space defined by \r
 49 
# Save registers to space defined by \r
47 
# We will change $at on the way
 50 
# We will change status: Disable ERL,EXL,UM,IE
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 51 
# These changes will be automatically reversed in REGISTER_LOAD
48 
.macro REGISTERS_STORE r
 52 
.macro REGISTERS_STORE_AND_EXC_RESET r
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	sw $at,EOFFSET_AT(\r)
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	sw $at,EOFFSET_AT(\r)
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	sw $v0,EOFFSET_V0(\r)
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	sw $v0,EOFFSET_V0(\r)
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	sw $v1,EOFFSET_V1(\r)
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	sw $v1,EOFFSET_V1(\r)
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	sw $a0,EOFFSET_A0(\r)
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	sw $a0,EOFFSET_A0(\r)
53 
	sw $a1,EOFFSET_A1(\r)
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	sw $a1,EOFFSET_A1(\r)
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87
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	sw $gp,EOFFSET_GP(\r)
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	sw $gp,EOFFSET_GP(\r)
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	sw $ra,EOFFSET_RA(\r)
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	sw $ra,EOFFSET_RA(\r)
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	sw $sp,EOFFSET_SP(\r)
 90 
	sw $sp,EOFFSET_SP(\r)
87 
 
 91 
 
88 
	mfc0 $at, $status
 92 
	mfc0 $t0, $status
- 
 
 93 
	mfc0 $t1, $epc
- 
 
 94
- 
 
 95 
	and $t2, $t0, REG_SAVE_MASK  # Save only KSU,EXL,ERL,IE
- 
 
 96 
	li $t3, ~(0x1f)
- 
 
 97 
	and $t0, $t0, $t3           # Clear KSU,EXL,ERL,IE
- 
 
 98
89 
	sw $at,EOFFSET_STATUS(\r)
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	sw $t2,EOFFSET_STATUS(\r)
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	mfc0 $at, $epc
 - 
 
91 
	sw $at,EOFFSET_EPC(\r)
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	sw $t1,EOFFSET_EPC(\r)
- 
 
 101 
	mtc0 $t0, $status
92 
.endm
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.endm
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 103 
 
94 
.macro REGISTERS_LOAD r
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.macro REGISTERS_LOAD r
- 
 
 105 
	# Update only UM,EXR,IE from status, the rest
- 
 
 106 
	# is controlled by OS and not bound to task
- 
 
 107 
	mfc0 $t0, $status
- 
 
 108 
	lw $t1,EOFFSET_STATUS(\r)
- 
 
 109 
 
- 
 
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	li $t2, ~REG_SAVE_MASK    # Mask UM,EXL,ERL,IE
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 111 
	and $t0, $t0, $t2
- 
 
 112
- 
 
 113 
	or $t0, $t0, $t1   # Copy UM,EXL,ERL,IE from saved status
- 
 
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	mtc0 $t0, $status
- 
 
 115
95 
	lw $v0,EOFFSET_V0(\r)
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	lw $v0,EOFFSET_V0(\r)
96 
	lw $v1,EOFFSET_V1(\r)
 117 
	lw $v1,EOFFSET_V1(\r)
97 
	lw $a0,EOFFSET_A0(\r)
 118 
	lw $a0,EOFFSET_A0(\r)
98 
	lw $a1,EOFFSET_A1(\r)
 119 
	lw $a1,EOFFSET_A1(\r)
99 
	lw $a2,EOFFSET_A2(\r)
 120 
	lw $a2,EOFFSET_A2(\r)
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	lw $at,EOFFSET_LO(\r)
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	lw $at,EOFFSET_LO(\r)
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	mtlo $at
 148 
	mtlo $at
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	lw $at,EOFFSET_HI(\r)
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	lw $at,EOFFSET_HI(\r)
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	mthi $at
 150 
	mthi $at
130 
 
 151 
 
131 
	lw $at,EOFFSET_STATUS(\r)
 - 
 
132 
	mtc0 $at, $status
 - 
 
133 
	lw $at,EOFFSET_EPC(\r)
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	lw $at,EOFFSET_EPC(\r)
134 
	mtc0 $at, $epc
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	mtc0 $at, $epc
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136 
	lw $at,EOFFSET_AT(\r)
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	lw $at,EOFFSET_AT(\r)
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	lw $sp,EOFFSET_SP(\r)
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	lw $sp,EOFFSET_SP(\r)
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 205 
 
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exception_handler:
 208 
exception_handler:
190 
	KERNEL_STACK_TO_K0
 209 
	KERNEL_STACK_TO_K0
- 
 
 210
- 
 
 211 
	mfc0 $k1, $cause
191 
	sub $k0, REGISTER_SPACE
 212 
	sub $k0, REGISTER_SPACE
- 
 
 213
- 
 
 214 
	sra $k1, $k1, 0x2     # cp0_exc_cause() part 1
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 215 
	andi $k1, $k1, 0x1f   # cp0_exc_cause() part 2
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	sub $k1, 8            # 8=SYSCALL
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- 
 
 218 
	beqz $k1, uspace_shortcut
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	add $k1, 8            # Revert $k1 back to correct exc number
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	REGISTERS_STORE $k0
 221 
	REGISTERS_STORE_AND_EXC_RESET $k0
193 
	add $sp, $k0, 0
 222 
	move $sp, $k0
194 
 
 223
195 
	add $a0, $sp, 0
224 
	move $a1, $sp
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	jal exception /* exception(register_space) */
 225 
	jal exc_dispatch      # exc_dispatch(excno, register_space)
197 
	nop
 226 
	move $a0, $k1
198 
 
 227 
 
199 
	REGISTERS_LOAD $sp
 228 
	REGISTERS_LOAD $sp
200 
	# The $sp is automatically restored to former value
 229 
	# The $sp is automatically restored to former value
201 
	eret
 230 
	eret
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	nop
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	nop
- 
 
 232 
 
- 
 
 233 
# it seems that mips reserves some space on stack for varfuncs???
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 234 
#define SS_ARG4   16
- 
 
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#define SS_SP     20
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#define SS_STATUS 24
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#define SS_EPC    28
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#define SS_RA     32
- 
 
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uspace_shortcut:
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	# We have a lot of space on the stack, with free use
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	sw $sp, SS_SP($k0)
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	move $sp, $k0
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 243 
	sw $ra, SS_RA($k0)
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 244 
 
- 
 
 245 
	mfc0 $t1, $epc
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 246 
	mfc0 $t0, $status
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 247 
	sw $t1,SS_EPC($sp)  # Save EPC
- 
 
 248
- 
 
 249 
	and $t2, $t0, REG_SAVE_MASK # Save only KSU,EXL,ERL,IE
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 250 
	li $t3, ~(0x1f)
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 251 
	and $t0, $t0, $t3           # Clear KSU,EXL,ERL
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 252 
	ori $t0, $t0, 0x1           # Set IE
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 253 
 
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	sw $t2,SS_STATUS($sp)
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	mtc0 $t0, $status
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 256 
 
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 257 
	jal syscall_handler
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 258 
	sw $v0, SS_ARG4($sp)        # save v0 - arg4 to stack
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 259 
 
- 
 
 260 
	# Restore RA
- 
 
 261 
	lw $ra, SS_RA($sp)
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 262
- 
 
 263 
	# restore epc+4
- 
 
 264 
	lw $t0,SS_EPC($sp)
- 
 
 265 
	addi $t0, $t0, 4
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 266 
	mtc0 $t0, $epc
- 
 
 267
- 
 
 268 
	# restore status
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 269 
	mfc0 $t0, $status
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 270 
	lw $t1,SS_STATUS($sp)
- 
 
 271 
 
- 
 
 272 
	li $t2, ~REG_SAVE_MASK      # Mask UM,EXL,ERL,IE
- 
 
 273 
	and $t0, $t0, $t2
- 
 
 274 
	or $t0, $t0, $t1            # Copy UM,EXL,ERL,IE from saved status
- 
 
 275 
	mtc0 $t0, $status
- 
 
 276
- 
 
 277 
	lw $sp,SS_SP($sp) # restore sp
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- 
 
 279 
	eret
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280
204 
tlb_refill_handler:
 281 
tlb_refill_handler:
205 
	KERNEL_STACK_TO_K0
 282 
	KERNEL_STACK_TO_K0
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	sub $k0, REGISTER_SPACE
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	sub $k0, REGISTER_SPACE
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	REGISTERS_STORE $k0
 284 
	REGISTERS_STORE_AND_EXC_RESET $k0
208 
	add $sp, $k0, 0
 285 
	add $sp, $k0, 0
209 
 
 286 
 
210 
	add $a0, $sp, 0
287 
	add $a0, $sp, 0
211 
	jal tlb_refill /* tlb_refill(register_space) */
 288 
	jal tlb_refill /* tlb_refill(register_space) */
212 
	nop
 289 
	nop
213 
 
 290 
 
214 
	REGISTERS_LOAD $sp
 291 
	REGISTERS_LOAD $sp
215 
 
 292 
 
216 
	eret
 293 
	eret
217 
	nop
 - 
 
218 
 
 294 
 
219 
cache_error_handler:
 295 
cache_error_handler:
220 
	KERNEL_STACK_TO_K0
 296 
	KERNEL_STACK_TO_K0
221 
	sub $sp, REGISTER_SPACE
 297 
	sub $sp, REGISTER_SPACE
222 
	REGISTERS_STORE $sp
 298 
	REGISTERS_STORE_AND_EXC_RESET $sp
223 
	add $sp, $k0, 0
 299 
	add $sp, $k0, 0
224 
 
 300 
 
225 
	jal cache_error
 301 
	jal cache_error
226 
	nop
 302 
	nop
227 
 
 303 
 
228 
	REGISTERS_LOAD $sp
 304 
	REGISTERS_LOAD $sp
229 
 
 305 
 
230 
	eret
 306 
	eret
231 
	nop
 - 
 
232 
 
 307 
 
233 
userspace_asm:
 308 
userspace_asm:
234 
	add $sp, $a0, 0
 309 
	add $sp, $a0, 0
235 
	add $v0, $a1, 0
 310 
	add $v0, $a1, 0
236 
	eret
 311 
	eret
237 
	nop
 - 
 
238 
 
 312