Microsoft Word Huong dan thuc hanh mips asm tren pcspim doc
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MIPSSSS, 5
| 5.6 Các lệnh mã giả mở rộng
Thiết lập các tham số trong menu Simulator -> Settings: SPIM set Bare Machine OFF, Allow Pseudo Instructions ON, Load Trap File OFF, Delayed Branches ON, Delayed Loads ON, Mapped IO OFF, Quiet OFF. Ví dụ theo sau thực hiện việc tính hóa đơn bữa ăn: tổng phí = tiền thức ăn + 8% tiền thuế +15% tiền phục vụ .text .globl main main: lui $10,0x1000 # initialize base register of the string lbu $8,($10) # get the first char of the string sll $0,$0,0 loop: beq $8,$0,halt # while ( char != '/0' ) sll $0,$0,0 # addiu $8,$8,0x20 # uncapitalize char sb $8,($10) # replace char in string addiu $10,$10,1 # advance the char pointer lbu $8,($10) # get the next char of the string j loop # end while sll $0,$0,0 halt: j halt # cycle sponge sll $0,$0,0 .data string: .asciiz "ABCDEFGHIJKLMNOP" ## End of file move d,s # copy the contents of the source register s to the # destination register d li d,value # load register $d with the positive or negative # integer "value". Value may be a 16 or a 32-bit integer. lw d,exp # Load register $d with the value at address "exp". # "exp" is often a symbolic address. la d,exp # load register $d with the address described by the # expression "exp". "exp" is often a symbolic address. nop # no operation. do nothing for one machine cycle. sw d,exp # Store register $d into the word at address exp. # exp can be any of several expression types # that evaluate to an address mul d,s,t # multiply $s by $t. put the result in $d div d,s,t # divide $s by $t. Put the quotient in $d. Operands are # two's complement. divu d,s,t # divide $s by $t. Put the quotient in $d. Operands are # unsigned. remu d,s,t # divide $s by $t. Put the remainder in $d. Operands are # unsigned. ## rest.asm ## ## Total restaurant bill calculator ## ## Register Use: ## ## $s0 meal cost ## $s1 tip rate ## $s2 tax rate ## $s3 total rate ## $s4 tax+tip dollars ## $s5 total bill .globl main # Get meal cost main: li $v0,4 # print prompt la $a0,prompt syscall li $v0,5 # input meal cost syscall move $s0,$v0 # save it in $s0 # Calculations lw $s1,tip # get tip rate lw $s2,tax # get tax rate addu $s3,$s1,$s2 # (tax + tip) in percent mul $s4,$s0,$s3 # mealcost*(total rate) div $s4,$s4,100 # mealcost*(total rate)/100 addu $s5,$s0,$s4 # total bill # Output li $v0,4 # print string la $a0,head1 # "tax plus tip" syscall move $a0,$s4 # get tax+tip li $v0,1 # print integer syscall # li $v0,4 # print string la $a0,head2 # "total cost" syscall move $a0,$s5 # get total li $v0,1 # print integer syscall # li $v0,10 # exit syscall .data tip: .word 15 # tip rate in percent tax: .word 8 # tax rate in percent prompt: .asciiz "Enter food cost: " head1 : .asciiz " Tax plus tip: " head2 : .asciiz "\n Total cost: " |