261 lines
3.9 KiB
ArmAsm
261 lines
3.9 KiB
ArmAsm
.file "kernel.s"
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.equ stack_ptr, 0x7FFFEFFC
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.equ baudrate, 0x0D
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.equ sys_led_port, 0xA0000000
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.equ sys_uart_baud, 0xA0000009
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.equ sys_uart_stat, 0xA0000008
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.equ sys_uart_data, 0xA0000004
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.equ sys_timer_sec, 0xA0000014
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.equ sys_timer_usec, 0xA0000010
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.section .kdata,"a"
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.align 2
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_k_stack: .space 256, 0
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_k_msg1: .asciiz "Exception at "
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_k_msg2: .asciiz "EPC : "
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_k_msg3: .asciiz "Cause : "
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_k_msg4: .asciiz "Status : "
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_k_msg5: .asciiz "BadVAddr : "
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_k_crlf: .asciiz "\r\n"
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_k_hextbl: .ascii "0123456789ABCDEF"
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.section .ktext,"ax"
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.align 2
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.globl _kputs
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.macro kpush reg
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addiu $sp, 4
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sw \reg, 0($sp)
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.endm
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.macro kpop reg
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lw \reg, 0($sp)
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addiu $sp, -4
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.endm
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_exc_handler:
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sw $sp, _k_stack
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la $sp, _k_stack
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kpush $8
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kpush $9
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kpush $10
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kpush $11
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kpush $12
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kpush $31
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.set noreorder
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# # Get BadVAddr
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# mfc0 $10, $8
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# kpush $10
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# # Get Status
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# mfc0 $10, $12
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# kpush $10
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# # Get Cause
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# mfc0 $10, $13
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# kpush $10
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# srl $10, 29
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# andi $11, $10, 4
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# # Get EPC
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# mfc0 $10, $14
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# kpush $10
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#
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# # Get real EPC
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# addu $10, $11
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# kpush $10
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#
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# # set uart
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# la $26, sys_uart_baud
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# addiu $27, $0, baudrate
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# sb $27, 0($26)
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#
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# # Print CRLF
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# la $11, _k_crlf
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# jal _kputs
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# nop
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#
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# # Print real EPC
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# la $11, _k_msg1
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# jal _kputs
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# nop
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# kpop $10
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# jal _kprint_word
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# nop
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# la $11, _k_crlf
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# jal _kputs
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# nop
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#
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# # Print EPC
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# la $11, _k_msg2
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# jal _kputs
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# nop
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# kpop $10
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# jal _kprint_word
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# nop
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# la $11, _k_crlf
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# jal _kputs
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# nop
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#
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# # Print Cause
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# la $11, _k_msg3
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# jal _kputs
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# nop
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# kpop $10
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# jal _kprint_word
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# nop
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# la $11, _k_crlf
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# jal _kputs
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# nop
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#
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# # Print Status
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# la $11, _k_msg4
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# jal _kputs
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# nop
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# kpop $10
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# jal _kprint_word
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# nop
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# la $11, _k_crlf
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# jal _kputs
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# nop
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#
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# # Print BadVAddr
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# la $11, _k_msg5
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# jal _kputs
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# nop
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# kpop $10
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# jal _kprint_word
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# nop
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# la $11, _k_crlf
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# jal _kputs
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# nop
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#
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# Set Error LED and ExcCode LEDs
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# Get Cause
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# mfc0 $26, $13
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# la $27, sys_led_port
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# srl $26, 2
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# andi $26, 0x000F
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# or $26, $27
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# sw $26, 0($27)
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# wait for all interrupts = 0
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#$w4x: mfc0 $26, $13
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# mfc0 $27, $12
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# srl $26, 8
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# srl $27, 8
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# and $26, $27
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# bnez $26, $w4x
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# Get return address
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mfc0 $26, $14
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$no_int: kpop $31
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kpop $12
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kpop $11
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kpop $10
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kpop $9
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kpop $8
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lw $sp, _k_stack
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# Return
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jr $26
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rfe
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.set reorder
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# word = $10
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_kprint_word:
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.set noreorder
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kpush $31
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kpush $10
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srl $10, 16
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jal _kprint_halfword
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nop
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kpop $10
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jal _kprint_halfword
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nop
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kpop $31
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jr $31
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nop
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.set noreorder
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# halfword = $10
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_kprint_halfword:
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.set noreorder
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kpush $31
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kpush $10
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srl $10, 8
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jal _kprint_byte
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nop
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kpop $10
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jal _kprint_byte
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nop
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kpop $31
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jr $31
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nop
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.set noreorder
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# byte = $10
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_kprint_byte:
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.set noreorder
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kpush $31
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kpush $10
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srl $10, 4
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jal _kprint_nibble
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nop
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kpop $10
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jal _kprint_nibble
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nop
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kpop $31
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jr $31
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nop
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.set noreorder
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_kprint_nibble:
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.set noreorder
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kpush $31
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kpush $10
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la $12, _k_hextbl
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andi $10, 0xF
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addu $12, $10
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lbu $10, 0($12)
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jal _ksaus
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nop
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kpop $10
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kpop $31
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jr $31
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nop
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.set noreorder
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# char = $10
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_ksaus:
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.set noreorder
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la $8, sys_uart_stat
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lbu $8, 0($8)
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la $9, sys_uart_data
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andi $8, 0x02
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bnez $8, _ksaus
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nop
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j $31
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sb $10, 0($9)
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.set reorder
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_kputs:
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.set noreorder
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kpush $11
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kpush $31
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$kpl: lbu $10, 0($11)
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addiu $11, 1
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blez $10, $kpex
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nop
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jal _ksaus
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nop
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j $kpl
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nop
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$kpex: kpop $31
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kpop $11
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jr $31
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nop
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.set reorder
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