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+ added an i8086 asm optimized strpcopy routine

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git-svn-id: trunk@31915 -
This commit is contained in:
nickysn 2015-10-02 16:42:25 +00:00
parent 3afc18f277
commit 7fb2418287
1 changed files with 47 additions and 0 deletions
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47
rtl/i8086/stringss.inc
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@ -15,3 +15,50 @@
**********************************************************************}
{$ifndef FPC_UNIT_HAS_STRPCOPY}
{$define FPC_UNIT_HAS_STRPCOPY}
function strpcopy(d : pchar;const s : string) : pchar;assembler;nostackframe;
const
{ used for an offset fixup for accessing the proc parameters in asm routines
that use nostackframe. We can't use the parameter name directly, because
i8086 doesn't support sp relative addressing. }
{$ifdef FPC_X86_CODE_FAR}
extra_param_offset = 2;
{$else FPC_X86_CODE_FAR}
extra_param_offset = 0;
{$endif FPC_X86_CODE_FAR}
asm
mov bx, sp
mov dx, ds // for far data models, backup ds; for near data models, use to initialize es
{$ifdef FPC_X86_DATA_NEAR}
mov es, dx
mov si, ss:[bx + 4 + extra_param_offset] // @d
mov di, ss:[bx + 2 + extra_param_offset] // @s
{$else FPC_X86_DATA_NEAR}
lds si, ss:[bx + 6 + extra_param_offset] // @d
les di, ss:[bx + 2 + extra_param_offset] // @s
{$endif FPC_X86_DATA_NEAR}
// we will no longer use bx for reading parameters, so save di there
// in order to be able to return it in the end
mov bx, di
{$ifdef FPC_ENABLED_CLD}
cld
{$endif FPC_ENABLED_CLD}
lodsb // load length in al
xor ah, ah
xchg cx, ax // 1 byte shorter than mov
shr cx, 1
rep movsw
adc cx, cx
rep movsb
xchg ax, cx // ax := 0 (1 byte shorter than xor al, al)
stosb // zero terminate the destination string
{$if defined(FPC_X86_DATA_FAR) or defined(FPC_X86_DATA_HUGE)}
mov ds, dx
mov dx, es // return segment of d in dx
{$endif}
xchg ax, bx // return original offset of d in ax
end;
{$endif FPC_UNIT_HAS_STRPCOPY}