ack/plat/msdos386/libsys/sys_cpyin.s
tkchia cba54b205b plat/msdos386: refactor, firm up, and optimize
- refactor code for transfer buffer reads/writes, real mode
   int 0x21 calls, and assembler segment declarations
 - define transfer buffer size in one place
 - beef up error checking for transfer buffer operations
   (prevent buffer overflows)
 - also optimize such operations to transfer dword by dword
   where feasible
2022-08-26 17:31:28 +00:00

33 lines
461 B
ArmAsm

#
! $Source$
! $State$
! $Revision$
#include "libsysasm.h"
! .sys_cpyin: copy ecx bytes from the transfer buffer to es:eax (= ds:eax).
! Preserve all registers, except the flags.
.extern .sys_cpyin
.sys_cpyin:
push eax
push ecx
push esi
push edi
movzx esi, (transfer_buffer_ptr)
xchg edi, eax
mov ds, (pmode_ds)
mov eax, ecx
shr ecx, 2
rep movs
andb al, 3
movb cl, al
rep movsb
mov eax, ss
mov ds, eax
pop edi
pop esi
pop ecx
pop eax
ret