79 lines
1.5 KiB
ArmAsm
79 lines
1.5 KiB
ArmAsm
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.text
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.globl _start
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_start:
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ld a0, 8(sp)
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jal ra, puts
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la a0, helloworld
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jal ra, puts
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la a0, incomingflag
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jal ra, puts
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ld t2, flagmyballs
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ror t2, t2, 01
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la t1, flagmyballs
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sd t2, 0(t1)
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la a0, flagmyballs
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jal ra, puts
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j exit
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len:
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mv t0, a0
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mv t1, t0
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lenloop:
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lb t2, (t1)
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beq t2, x0, lencleanup
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addi t1, t1, 1
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j lenloop
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lencleanup:
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sub a0, t1, t0
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ret
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puts:
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#here a0 should be the pointer to the string
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#save s2 becuase we are gonna use it
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addi sp, sp, -16
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sd s2, 12(sp)
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#save a0 because we need it later
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mv s2, a0
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#get length because the stdout systemcall needs it in a2
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addi sp, sp, -16 # Allocate stack space
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sd ra, 12(sp) # Save return address
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jal ra, len
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ld ra, 12(sp) # Restore return address
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addi sp, sp, 16 # Deallocate stack space
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#a0 should be the length
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mv a2, a0 #stdout expects it in a2
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li a0, 1 # file descriptor = 1 (stdout)
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li a7, 64 # syscall write (64)
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mv a1, s2 #this should still be the pointer to the text
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#restore s2 for the next guy
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ld s2, 12(sp)
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addi sp, sp, 16
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ecall
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ret
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exit:
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li a0, 0 # exit code
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li a7, 93 # syscall exit
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ecall
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.data
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helloworld: .asciz "Hello! It works!!!\n"
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incomingflag: .asciz "The flag you gotta fix should be right after the newline\n"
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flagmyballs:
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# .dword 0x7370617263363400
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.dword 0x0343663726170730
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