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Fix fizzbuzz output length

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dwrz
2026-10-22 14:38:55 +00:00
parent 163f74bc0c
commit 30f2ccddda
1 changed files with 7 additions and 5 deletions
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fizzbuzz/fizzbuzz.s
+7 -5
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@@ -110,9 +110,10 @@ save_to_buffer_loop:
cmp $0, %rcx # Have we processed all digits? cmp $0, %rcx # Have we processed all digits?
jne save_to_buffer_loop # If not, loop again. jne save_to_buffer_loop # If not, loop again.
# We're done moving data from the stack to the buffer. # We're done moving data from the stack to the buffer.
# Let's add a newline to the end of our digits. # Let's add a newline right after our digits.
# The ASCII integer representation of "\n" is 10. # The ASCII integer representation of "\n" is 10.
movb $10, number_string + 3 # %rdx is left pointing at the newline, so callers can compute length.
movb $10, (%rdx)
mov %rbp, %rsp mov %rbp, %rsp
pop %rbp pop %rbp
ret ret
@@ -159,9 +160,10 @@ print_counter:
mov $4, %rax mov $4, %rax
mov $1, %rbx mov $1, %rbx
mov $number_string, %rcx # Set the buffer the kernel should use. mov $number_string, %rcx # Set the buffer the kernel should use.
# Print 3 digits + 1 newline = 4 bytes. # _itoa leaves %rdx pointing at the newline after the digits.
# FIX: this is wrong -- we're not always printing 4 bytes. # Length = (newline address - buffer start) + 1 for the newline.
mov $4, %rdx sub $number_string, %rdx
inc %rdx
jmp print_and_return jmp print_and_return
print_fizz: print_fizz:
mov $fizz, %rcx mov $fizz, %rcx