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# Copyright 2022 Gabriel Jensen.
# This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0.
# If a copy of the MPL was not distributed with this file, You can obtain one at https://mozilla.org/MPL/2.0/.
.globl zap_strcp
zap_strcp:
# rax: Address of the current input character.
# rdi: Address of the first input character.
# rsi: Address of the current output character.
# rdx: Current character.
movq %rdi,%rax
# Iterate over the strings:
.loop:
# Copy character:
movb (%rax),%dl # Move it into a register...
movb %dl,(%rsi) # ... and then back into memory.
# Check if we have reached the null-terminator:
testb %dl,%dl
jz .done
# Continue to the next character:
incq %rax
incq %rsi
jmp .loop
# Finish:
.done:
# Get the length of the (input) string:
subq %rdi,%rax
decq %rax # We do not count the null-terminator in the string length.
ret
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