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hex0.S: optimize read/write_byte functions.

This commit is contained in:
Andrius Štikonas 2022-07-16 01:06:47 +01:00
parent 3e95bb7d48
commit 4afbfc56cc
1 changed files with 16 additions and 16 deletions
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32
amd64/Development/hex0.S
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@ -136,7 +136,6 @@ print:
# update the sum and store in output
shl r14, 4
add rax, r14
mov [output], al
# flip the toggle
mov r15, -1
@ -217,32 +216,36 @@ terminate:
call [rcx+16] # fout->close()
add rsp, 16 # deallocate stack
ret
ret # return to UEFI
read_byte:
sub rsp, 24 # allocate stack
mov qword ptr [size], 1 # size = 1
mov rcx, [fin] # arg1 = fin
lea rdx, [size] # arg2 = &size
lea r8, [input] # arg3 = &input
push 1 # size = 1
mov rdx, rsp # arg2 = &size
push 1 # allocate stack
mov r8, rsp # arg3 = &input
sub rsp, 24 # allocate stack
call [rcx+32] # fin->read()
add rsp, 24 # deallocate stack
pop rax # save input to rax
pop rbx # save size to rbx
# If the file ended (0 bytes read) terminate
cmp qword ptr [size], 0 # if size == 0
test rbx, rbx # if size == 0
je terminate # then we are done
movzx rax, byte ptr [input] # save character to rax
ret # return
# Writes byte stored in al
write_byte:
sub rsp, 24 # allocate stack
mov qword ptr [size], 1 # size = 1
mov rcx, [fout] # arg1 = fout
lea rdx, [size] # arg2 = &size
lea r8, [output] # arg3 = &output
push 1 # size = 1
mov rdx, rsp # arg2 = &size
push rax # allocate stack
mov r8, rsp # arg3 = &output
sub rsp, 24 # allocate stack
call [rcx+40] # fout->write()
add rsp, 24 # deallocate stack
add rsp, 40 # deallocate stack
ret # return
.data
@ -252,9 +255,6 @@ SystemBoot: .quad 0
RootDir: .quad 0
fin: .quad 0
fout: .quad 0
size: .quad 0
input: .byte 0
output: .quad 0
# Protocol GUIDs
LOADED_IMAGE_PROTOCOL: