andrius
/
stage0-uefi
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

hex0.S: backport some optimizations from stage0-posix-amd64.

This commit is contained in:
Andrius Štikonas 2022-07-16 20:09:53 +01:00
parent be031a577c
commit 71bca6e471
1 changed files with 13 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
amd64/Development/hex0.S
View File

@ -106,10 +106,11 @@ loop_options2: # Skip argv[1]
add rsp, 40 # deallocate stack
# Our flag for byte processing
mov r15, -1
push -1
pop r15 # r15 = -1
# temp storage for the sum
mov r14, 0
xor r14d, r14d # r14 = 0
loop:
# Read a byte
@ -119,16 +120,16 @@ loop:
call hex
# Deal with -1 values
cmp rax, 0
test rax, rax
jl loop
# deal with toggle
cmp r15, 0
test r15, r15
jge print
# process first byte of pair
mov r14, rax
mov r15, 0
xor r15d, r15d # r15 = 0
jmp loop
# process second byte of pair
@ -138,7 +139,8 @@ print:
add rax, r14
# flip the toggle
mov r15, -1
push -1
pop r15 # r15 = -1
call write_byte
@ -189,7 +191,8 @@ purge_comment:
jne purge_comment
# Otherwise return -1
mov rax, -1
push -1
pop rax # rax = -1
ret
ascii_num:
@ -205,7 +208,8 @@ ascii_high:
ret
ascii_other:
mov rax, -1
push -1
pop rax # rax = -1
ret
terminate:
@ -222,7 +226,7 @@ read_byte:
mov rcx, [fin] # arg1 = fin
push 1 # size = 1
mov rdx, rsp # arg2 = &size
push 1 # allocate stack
push rbx # allocate stack
mov r8, rsp # arg3 = &input
sub rsp, 24 # allocate stack
call [rcx+32] # fin->read()