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# Skips spaces and equal signs (used by CNF parser)
skipspace:
# a0 - Input string
# Return: v0 - Address to first non-space character.
lbu $v1, 0($a0)
nop
beq $v1, ' ', .skip
nop
beq $v1, '=', .skip
nop
jr $ra
move $v0, $a0
.skip:
b skipspace
addiu $a0, 1
# Copies a string until a CR/LF or space is encountered
getline:
# a0 - Output address
# a1 - String to copy from
lbu $v0, 0($a1)
addiu $a1, 1
beqz $v0, .end
nop
beq $v0, 0x0D, .end
nop
beq $v0, 0x0A, .end
nop
beq $v0, ' ', .end
nop
sb $v0, 0($a0)
b getline
addiu $a0, 1
.end:
jr $ra
sb $0, 0($a0)
# strcasestr implementation
strcasestr:
# a0 - String to search
# a1 - String to find
addiu $sp, -24
sw $ra, 0($sp)
sw $s0, 4($sp)
sw $s1, 8($sp)
sw $a1, 16($sp)
.scan_start:
sw $a0, 12($sp)
.comp_loop:
lbu $s0, 0($a0) # Load character from A and B
lbu $s1, 0($a1)
beqz $s0, .end_strcasestr
nop
beqz $s1, .found
nop
sw $a0, 20($sp) # Save a0 parameter
jal toupper # tolower character A
move $a0, $s0
move $s0, $v0
jal toupper # tolower character B
move $a0, $s1
move $s1, $v0
lw $a0, 20($sp) # Restore a0 parameter
addiu $a1, 1
addiu $a0, 1
beq $s0, $s1, .comp_loop # If value matches continue compare
nop
.end_strcasestr:
lw $a0, 12($sp) # Rescan from next character of string A
lw $a1, 16($sp)
addiu $a0, 1
lbu $v0, 0($a0)
nop
beqz $v0, .not_found # If terminator is reached, string is not found
nop
b .scan_start
nop
.not_found:
b .quit
move $v0, $0
.found:
lw $v0, 12($sp) # Return address of string match
.quit:
lw $ra, 0($sp)
lw $s0, 4($sp)
lw $s1, 8($sp)
jr $ra
addiu $sp, 24
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