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[MIPS Assembly/ en] fixing line length
Some lines were greater than 80 characters long, which causes some unaligned wrapping of comments on the website. This PR reduces all lines' length to a maximum of 80.
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Keating950
GitHub
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1274a06704
@ -39,28 +39,30 @@ gateways and routers.
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_float: .float 3.14 # 4 bytes
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_double: .double 7.0 # 8 bytes
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.align 2 # Memory alignment of data, where
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# number indicates byte alignment in
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# powers of 2. (.align 2 represents
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# word alignment since 2^2 = 4 bytes)
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.align 2 # Memory alignment of data, where
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# number indicates byte alignment
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# in powers of 2. (.align 2
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# represents word alignment since
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# 2^2 = 4 bytes)
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.text # Section that contains instructions
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# and program logic
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.text # Section that contains
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# instructions and program logic
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.globl _main # Declares an instruction label as
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# global, making it accessible to
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# other files
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_main: # MIPS programs execute instructions
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# sequentially, where the code under
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# this label will be executed firsts
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_main: # MIPS programs execute
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# instructions sequentially, where
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# the code under this label will be
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# executed first
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# Let's print "hello world"
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la $a0, hello_world # Load address of string stored in
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# memory
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li $v0, 4 # Load the syscall value (indicating
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# type of functionality)
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syscall # Perform the specified syscall with
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# the given argument ($a0)
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la $a0, hello_world # Load address of string stored
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# in memory
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li $v0, 4 # Load the syscall value (number
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# indicating which syscall to make)
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syscall # Perform the specified syscall
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# with the given argument ($a0)
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# Registers (used to hold data during program execution)
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# $t0 - $t9 # Temporary registers used for
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@ -79,22 +81,24 @@ gateways and routers.
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# Types of load/store instructions
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la $t0, label # Copy the address of a value in
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# memory specified by the label into
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# register $t0
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# memory specified by the label
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# into register $t0
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lw $t0, label # Copy a word value from memory
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lw $t1, 4($s0) # Copy a word value from an address
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# stored in a register with an offset
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# of 4 bytes (addr + 4)
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lb $t2, label # Copy a byte value to the lower order
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# portion of the register $t2
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# stored in a register with an
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# offset of 4 bytes (addr + 4)
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lb $t2, label # Copy a byte value to the
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# lower order portion of
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# the register $t2
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lb $t2, 0($s0) # Copy a byte value from the source
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# address in $s0 with offset 0
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# Same idea with 'lh' for halfwords
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sw $t0, label # Store word value into memory address
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# mapped by label
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sw $t0, label # Store word value into
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# memory address mapped by label
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sw $t0, 8($s0) # Store word value into address
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# specified in $s0 and offset of 8 bytes
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# specified in $s0 and offset of
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# 8 bytes
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# Same idea using 'sb' and 'sh' for bytes and halfwords. 'sa' does not exist
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### Math ###
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@ -108,20 +112,22 @@ gateways and routers.
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mul $t2, $t0, $t1 # $t2 = $t0 * $t1
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div $t2, $t0, $t1 # $t2 = $t0 / $t1 (Might not be
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# supported in some versons of MARS)
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div $t0, $t1 # Performs $t0 / $t1. Get the quotient
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# using 'mflo' and remainder using 'mfhi'
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div $t0, $t1 # Performs $t0 / $t1. Get the
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# quotient using 'mflo' and
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# remainder using 'mfhi'
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# Bitwise Shifting
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sll $t0, $t0, 2 # Bitwise shift to the left with
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# immediate (constant value) of 2
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sllv $t0, $t1, $t2 # Shift left by a variable amount in
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# register
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sllv $t0, $t1, $t2 # Shift left by a variable amount
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# in register
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srl $t0, $t0, 5 # Bitwise shift to the right (does
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# not sign preserve, sign-extends with 0)
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srlv $t0, $t1, $t2 # Shift right by a variable amount in
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# a register
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sra $t0, $t0, 7 # Bitwise arithmetic shift to the right
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# (preserves sign)
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# not sign preserve, sign-extends
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# with 0)
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srlv $t0, $t1, $t2 # Shift right by a variable amount
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# in a register
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sra $t0, $t0, 7 # Bitwise arithmetic shift to
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# the right (preserves sign)
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srav $t0, $t1, $t2 # Shift right by a variable amount
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# in a register
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@ -146,7 +152,8 @@ gateways and routers.
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# $t0 == $t1, otherwise
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# execute the next line
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bne $t0, $t1, reg_neq # Branches when $t0 != $t1
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b branch_target # Unconditional branch, will always execute
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b branch_target # Unconditional branch, will
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# always execute
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beqz $t0, req_eq_zero # Branches when $t0 == 0
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bnez $t0, req_neq_zero # Branches when $t0 != 0
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bgt $t0, $t1, t0_gt_t1 # Branches when $t0 > $t1
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@ -155,8 +162,9 @@ gateways and routers.
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blt $t0, $t1, t0_gt_t1 # Branches when $t0 < $t1
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ble $t0, $t1, t0_gte_t1 # Branches when $t0 <= $t1
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bltz $t0, t0_lt0 # Branches when $t0 < 0
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slt $s0, $t0, $t1 # Instruction that sends a signal when
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# $t0 < $t1 with result in $s0 (1 for true)
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slt $s0, $t0, $t1 # Instruction that sends a signal
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# when $t0 < $t1 with result in $s0
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# (1 for true)
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# Simple if statement
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# if (i == j)
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@ -183,14 +191,14 @@ gateways and routers.
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# max = c;
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# Let $s0 = a, $s1 = b, $s2 = c, $v0 = return register
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ble $s0, $s1, a_LTE_b # if (a <= b) branch(a_LTE_b)
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ble $s0, $s2, max_C # if (a > b && a <=c) branch(max_C)
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ble $s0, $s1, a_LTE_b # if(a <= b) branch(a_LTE_b)
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ble $s0, $s2, max_C # if(a > b && a <=c) branch(max_C)
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move $v0, $s1 # else [a > b && a > c] max = a
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j done # Jump to the end of the program
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a_LTE_b: # Label for when a <= b
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ble $s1, $s2, max_C # if (a <= b && b <= c) branch(max_C)
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move $v0, $s1 # if (a <= b && b > c) max = b
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ble $s1, $s2, max_C # if(a <= b && b <= c) branch(max_C)
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move $v0, $s1 # if(a <= b && b > c) max = b
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j done # Jump to done
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max_C:
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@ -204,9 +212,11 @@ gateways and routers.
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instruction to continue its execution
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li $t0, 0
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while:
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bgt $t0, 10, end_while # While $t0 is less than 10, keep iterating
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bgt $t0, 10, end_while # While $t0 is less than 10,
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# keep iterating
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addi $t0, $t0, 1 # Increment the value
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j while # Jump back to the beginning of the loop
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j while # Jump back to the beginning of
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# the loop
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end_while:
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# 2D Matrix Traversal
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@ -246,7 +256,8 @@ gateways and routers.
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# How about recursion?
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# This is a bit more work since we need to make sure we save and restore
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# the previous PC in $ra since jal will automatically overwrite on each call
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# the previous PC in $ra since jal will automatically overwrite
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# on each call
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li $a0, 3
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jal fact
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