Conditional branches

(beq, bne, slt, slti,  sltu( chck unsigned number) )

	MIPS
if ( i == j )   f = g + h; else   g = g - h;	assume: f = $s0, g = $s1,  h = $s2 i = $s3,  j = $s4 #--------------- bne   $s3, $s4, ELSE add   $s0, $s1, $2 j    Exit     # skip else ELSE: sub   $s1, $s1, $s2 Exit:
if ( i < j )   f = g + h; else  g = g - h;	slt $t0, $s3, $s4    # i < j, $t0 = 0, else $t0=1 bne $t0, 1, Else add    $s0, $s1, $s2 j    Exit      # skip else part Else: sub $s1, $s1, $s2 Exit:

While Loop

	MIPS
while ( save[i] == k )   i += 1;	assume:  i = $s3, k = $s5 , save[0] = $s6 #------------------------ (convert lw $t0, 4i($s6) ) Loop: sll    $s3, $s3, 2        #  i = 4i add  $t1, $s3, $s6    # 4i($s6) lw    $t0, 0($t1)         #  lw $t0, 4i($s6) bne $t0, $s5, Exit addi $s3,$s3, 1 j  Loop                      # loop again Exit:

Case / Switch Statement

switch (k) {  case 0:  f = i + j; break;  case 1:  f = g + h; break;  case 2:  f = i - j;  break;  case 3:  f = g - h; break; } --------------------------------------- assume:  f = $s0, g = $s1, h = $s2, i = $s3, j = $s4, k = $s5 $t2 = 4 $t4 contains address of an array, jumptable

slt $t0, $s5, $0   # k < 0; $t0 = 1; else $t0 =0 beq $t0, 1, Exit  # k < 0, go to L1 beq $s5, 0, L0   # k = 0, go to L2 beq $s5, 1, L1 beq $s5, 2, L2 beq $s5, 3, L3 slt  $t0, 3, $s5  # k > 3, $t0 = 1; else $t0 = 0 beq $t0, 1, Exit L0:   add $s0, $s3, $s4   j Exit L1:   add $s0, $s1, $s2   j Exit L2:   sub $s0, $3, $s4   j Exit L3:   sub $s0, $s1,$s2   j Exit Exit:

Procedures

	MIPS
int leaf_example ( int g, int h, int i, int j ) {    int f;    f = ( g + h )  - ( i + j );    return f; } f, g, h , i,  j are local variables in the procedure. any declaired variable in procedure use $s0  - $s7	addi $sp, $sp, -12 sw    $t1,  8($sp) sw    $t0,  4($sp) sw    $s0, 0($sp) add $t0, $a0, $a1 add $t1, $a2, $a3 sub $s0, $t0, $t1 add $v0, $s0, $0 lw  $s0, 0($sp) lw  $t0,  4($sp) lw  $t1,  8($sp) addi $sp, $sp, 12 jr $ra
Does it work??? If I don’t store in the stack? add $v0, $a0, $a1 add $t0, $a2, $a3 sub $v0, $v0, $t0 jr $ra	is it right???? #-------------------------------- addi $sp, $sp, -8 sw $t0, 4($sp) sw $t1, 0($sp) add $t0, $a0, $a1 add $t1, $a2, $a3 sub $v0, $t0, $t1 lw $t1, 0($sp) lw $t0, 4($sp) addi $sp, $sp,8 jr $ra

Nested Procedures

int fact ( int n ) {       if ( n < 1 ) return (1);    else           return ( N * fact ( n - 1)); }

#---------------------- fact: addi   $sp, $sp, -8 sw     $ra, 4($sp)    # save the return address sw     $a0, 0($sp)   # save the argument n slti   $t0, $a0, 1      # n < 1; $t0 = 1; else $t0 = 0 beq  $t0, $0, L1     # n >= 1 go to L1 addi  $v0, $0, 1      # return 1 addi  $sp, $sp, 8 jr    $ra L1: addi  $a0, $a0, -1    # n >= 1; argument gets ( n - 1 ) jal fact lw     $a0, 0($sp) lw     $v0, 4($sp) addi $sp, $sp,8 mul   $v0, $a0, $v0    # return n * fact ( n - 1 ) jr     $ra

int fact ( int n ) {       if ( n < 1 ) return (1);    else           return ( N * fact ( n - 1)); }

2 values need to be stored: n, return value fact: addi $sp, $sp, -8 sw $a0, 4($sp) sw $ra, 0($sp) slt $t0, $a0, 1        # $a0 < 1 , $t0 = 1; else $t0 = 0 beq $t0, $0, L1      # n >= 1 # n < 1 add $v0, $0, 1       # return 1   addi $sp, 8($sp)   # jr $ra L1:  # (n >= 1) addi $a0, $a0, -1   # n-- jal  fact lw $ra, 0($sp) lw $a0, 4($sp) addi $sp, $sp, -8 mul $v0, $a0, $v0   # N * fact (n -1) jr $ra