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hex0.S: use r14 to store system->boot->open_protocol rather than system->boot. 

Also reuse r14 for rootdir and free up rsi for further optimizations.
This commit is contained in:
Andrius Štikonas 2022-07-17 12:30:29 +01:00
parent f5bae9d646
commit 1d3ea9e5c0
1 changed files with 8 additions and 8 deletions
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16
amd64/Development/hex0.S
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@ -11,10 +11,9 @@
# but we need to leave stack space
# Registers:
# rsi rootdir
# r12 in/fin: input file name, later reused for handle
# r13 out/fout: output file name, later reused for handle
# r14 system->boot from UEFI, later reused for hex0 algorithm
# r14 system->boot->open_protocol from UEFI, later reused for hex0 algorithm, later reused for rootdir
# r15 image_handle from UEFI, later reused for hex0 algorithm
.global _start
@ -23,7 +22,8 @@
_start:
mov rbp, rsp # save stack pointer
mov r15, rcx # save image_handle
mov r14, [rdx+96] # save system->boot
mov r14, [rdx+96] # system->boot
mov r14, [r14+280] # system->boot->open_protocol
# Open Loaded Image protocol
push rax # allocate stack for image
@ -38,7 +38,7 @@ _start:
mov r9, rcx # arg4 = image_handle
# arg1 = ImageHandle (already set)
sub rsp, 32 # allocate stack
call [r14+280] # system->boot->open_protocol(image_handle, &guid, &image, image_handle, 0, EFI_OPEN_PROTOCOL_BY_HANDLE_PROTOCOL);
call r14 # system->boot->open_protocol(image_handle, &guid, &image, image_handle, 0, EFI_OPEN_PROTOCOL_BY_HANDLE_PROTOCOL);
mov rax, [rsp+64] # get image
# Command line args
@ -77,7 +77,7 @@ loop_options2: # Skip argv[1]
mov r9, r15 # arg4 = image_handle
mov rcx, [rcx+24] # arg1 = root_device = image->device
sub rsp, 32 # allocate stack
call [r14+280] # system->boot->open_protocol(root_device, &guid, &rootfs, image_handle, 0, EFI_OPEN_PROTOCOL_BY_HANDLE_PROTOCOL);
call r14 # system->boot->open_protocol(root_device, &guid, &rootfs, image_handle, 0, EFI_OPEN_PROTOCOL_BY_HANDLE_PROTOCOL);
mov rcx, [rsp+64] # get rootfs
# Get rootfs
@ -85,7 +85,7 @@ loop_options2: # Skip argv[1]
mov rdx, rsp # arg2 = &rootdir
sub rsp, 16 # allocate stack
call [rcx+8] # rootfs->open_volume(rootfs, &rootdir)
mov rsi, [rsp+16] # save &rootdir
mov r14, [rsp+16] # save &rootdir
# Open file for writing
push rdx # allocate stack for fout
@ -93,7 +93,7 @@ loop_options2: # Skip argv[1]
push 0 # arg5 = 0
mov r9, 0x8000000000000003 # arg4 = EFI_FILE_MODE_CREATE| EFI_FILE_MODE_WRITE | EFI_FILE_MODE_READ
mov r8, r13 # arg3 = out
mov rcx, rsi # arg1 = rootdir
mov rcx, r14 # arg1 = rootdir
sub rsp, 32 # allocate stack
call [rcx+8] # rootdir->open()
mov r13, [rsp+40] # get fout
@ -104,7 +104,7 @@ loop_options2: # Skip argv[1]
push 1 # arg5 = EFI_FILE_READ_ONLY
mov r9, 1 # arg4 = EFI_FILE_MODE_READ
mov r8, r12 # arg3 = in
mov rcx, rsi # arg1 = rootdir
mov rcx, r14 # arg1 = rootdir
sub rsp, 32 # allocate stack
call [rcx+8] # rootdir->open()
mov r12, [rsp+40] # get fin