; inffasx64.asm is a hand tuned assembler version of inffast.c - fast decoding

; version for AMD64 on Windows using Microsoft C compiler

;

; inffasx64.asm is automatically convert from AMD64 portion of inffas86.c

; inffasx64.asm is called by inffas8664.c, which contain more info.





; to compile this file, I use option

;   ml64.exe /Flinffasx64 /c /Zi inffasx64.asm

;   with Microsoft Macro Assembler (x64) for AMD64

;

;   ml64.exe is given with Visual Studio 2005, Windows 2003 server DDK

;

;   (you can get Windows 2003 server DDK with ml64 and cl.exe for AMD64 from 

;      http://www.microsoft.com/whdc/devtools/ddk/default.mspx for low price)

;



.code

inffas8664fnc PROC



; see http://weblogs.asp.net/oldnewthing/archive/2004/01/14/58579.aspx and

; http://msdn.microsoft.com/library/en-us/kmarch/hh/kmarch/64bitAMD_8e951dd2-ee77-4728-8702-55ce4b5dd24a.xml.asp

;

; All registers must be preserved across the call, except for

;   rax, rcx, rdx, r8, r-9, r10, and r11, which are scratch.





	mov [rsp-8],rsi

	mov [rsp-16],rdi

	mov [rsp-24],r12

	mov [rsp-32],r13

	mov [rsp-40],r14

	mov [rsp-48],r15

	mov [rsp-56],rbx



	mov rax,rcx



	mov	[rax+8], rbp       ; /* save regs rbp and rsp */

	mov	[rax], rsp



	mov	rsp, rax          ; /* make rsp point to &ar */



	mov	rsi, [rsp+16]      ; /* rsi  = in */

	mov	rdi, [rsp+32]      ; /* rdi  = out */

	mov	r9, [rsp+24]       ; /* r9   = last */

	mov	r10, [rsp+48]      ; /* r10  = end */

	mov	rbp, [rsp+64]      ; /* rbp  = lcode */

	mov	r11, [rsp+72]      ; /* r11  = dcode */

	mov	rdx, [rsp+80]      ; /* rdx  = hold */

	mov	ebx, [rsp+88]      ; /* ebx  = bits */

	mov	r12d, [rsp+100]    ; /* r12d = lmask */

	mov	r13d, [rsp+104]    ; /* r13d = dmask */

                                          ; /* r14d = len */

                                          ; /* r15d = dist */





	cld

	cmp	r10, rdi

	je	L_one_time           ; /* if only one decode left */

	cmp	r9, rsi



    jne L_do_loop





L_one_time:

	mov	r8, r12           ; /* r8 = lmask */

	cmp	bl, 32

	ja	L_get_length_code_one_time



	lodsd                         ; /* eax = *(uint *)in++ */

	mov	cl, bl            ; /* cl = bits, needs it for shifting */

	add	bl, 32             ; /* bits += 32 */

	shl	rax, cl

	or	rdx, rax          ; /* hold |= *((uint *)in)++ << bits */

	jmp	L_get_length_code_one_time



ALIGN 4

L_while_test:

	cmp	r10, rdi

	jbe	L_break_loop

	cmp	r9, rsi

	jbe	L_break_loop



L_do_loop:

	mov	r8, r12           ; /* r8 = lmask */

	cmp	bl, 32

	ja	L_get_length_code    ; /* if (32 < bits) */



	lodsd                         ; /* eax = *(uint *)in++ */

	mov	cl, bl            ; /* cl = bits, needs it for shifting */

	add	bl, 32             ; /* bits += 32 */

	shl	rax, cl

	or	rdx, rax          ; /* hold |= *((uint *)in)++ << bits */



L_get_length_code:

	and	r8, rdx            ; /* r8 &= hold */

	mov	eax, [rbp+r8*4]  ; /* eax = lcode[hold & lmask] */



	mov	cl, ah            ; /* cl = this.bits */

	sub	bl, ah            ; /* bits -= this.bits */

	shr	rdx, cl           ; /* hold >>= this.bits */



	test	al, al

	jnz	L_test_for_length_base ; /* if (op != 0) 45.7% */



	mov	r8, r12            ; /* r8 = lmask */

	shr	eax, 16            ; /* output this.val char */

	stosb



L_get_length_code_one_time:

	and	r8, rdx            ; /* r8 &= hold */

	mov	eax, [rbp+r8*4] ; /* eax = lcode[hold & lmask] */



L_dolen:

	mov	cl, ah            ; /* cl = this.bits */

	sub	bl, ah            ; /* bits -= this.bits */

	shr	rdx, cl           ; /* hold >>= this.bits */



	test	al, al

	jnz	L_test_for_length_base ; /* if (op != 0) 45.7% */



	shr	eax, 16            ; /* output this.val char */

	stosb

	jmp	L_while_test



ALIGN 4

L_test_for_length_base:

	mov	r14d, eax         ; /* len = this */

	shr	r14d, 16           ; /* len = this.val */

	mov	cl, al



	test	al, 16

	jz	L_test_for_second_level_length ; /* if ((op & 16) == 0) 8% */

	and	cl, 15             ; /* op &= 15 */

	jz	L_decode_distance    ; /* if (!op) */



L_add_bits_to_len:

	sub	bl, cl

	xor	eax, eax

	inc	eax

	shl	eax, cl

	dec	eax

	and	eax, edx          ; /* eax &= hold */

	shr	rdx, cl

	add	r14d, eax         ; /* len += hold & mask[op] */



L_decode_distance:

	mov	r8, r13           ; /* r8 = dmask */

	cmp	bl, 32

	ja	L_get_distance_code  ; /* if (32 < bits) */



	lodsd                         ; /* eax = *(uint *)in++ */

	mov	cl, bl            ; /* cl = bits, needs it for shifting */

	add	bl, 32             ; /* bits += 32 */

	shl	rax, cl

	or	rdx, rax          ; /* hold |= *((uint *)in)++ << bits */



L_get_distance_code:

	and	r8, rdx           ; /* r8 &= hold */

	mov	eax, [r11+r8*4] ; /* eax = dcode[hold & dmask] */



L_dodist:

	mov	r15d, eax         ; /* dist = this */

	shr	r15d, 16           ; /* dist = this.val */

	mov	cl, ah

	sub	bl, ah            ; /* bits -= this.bits */

	shr	rdx, cl           ; /* hold >>= this.bits */

	mov	cl, al            ; /* cl = this.op */



	test	al, 16             ; /* if ((op & 16) == 0) */

	jz	L_test_for_second_level_dist

	and	cl, 15             ; /* op &= 15 */

	jz	L_check_dist_one



L_add_bits_to_dist:

	sub	bl, cl

	xor	eax, eax

	inc	eax

	shl	eax, cl

	dec	eax                 ; /* (1 << op) - 1 */

	and	eax, edx          ; /* eax &= hold */

	shr	rdx, cl

	add	r15d, eax         ; /* dist += hold & ((1 << op) - 1) */



L_check_window:

	mov	r8, rsi           ; /* save in so from can use it's reg */

	mov	rax, rdi

	sub	rax, [rsp+40]      ; /* nbytes = out - beg */



	cmp	eax, r15d

	jb	L_clip_window        ; /* if (dist > nbytes) 4.2% */



	mov	ecx, r14d         ; /* ecx = len */

	mov	rsi, rdi

	sub	rsi, r15          ; /* from = out - dist */



	sar	ecx, 1

	jnc	L_copy_two           ; /* if len % 2 == 0 */



	rep     movsw

	mov	al, [rsi]

	mov	[rdi], al

	inc	rdi



	mov	rsi, r8           ; /* move in back to %rsi, toss from */

	jmp	L_while_test



L_copy_two:

	rep     movsw

	mov	rsi, r8           ; /* move in back to %rsi, toss from */

	jmp	L_while_test



ALIGN 4

L_check_dist_one:

	cmp	r15d, 1            ; /* if dist 1, is a memset */

	jne	L_check_window

	cmp	[rsp+40], rdi      ; /* if out == beg, outside window */

	je	L_check_window



	mov	ecx, r14d         ; /* ecx = len */

	mov	al, [rdi-1]

	mov	ah, al



	sar	ecx, 1

	jnc	L_set_two

	mov	[rdi], al

	inc	rdi



L_set_two:

	rep     stosw

	jmp	L_while_test



ALIGN 4

L_test_for_second_level_length:

	test	al, 64

	jnz	L_test_for_end_of_block ; /* if ((op & 64) != 0) */



	xor	eax, eax

	inc	eax

	shl	eax, cl

	dec	eax

	and	eax, edx         ; /* eax &= hold */

	add	eax, r14d        ; /* eax += len */

	mov	eax, [rbp+rax*4] ; /* eax = lcode[val+(hold&mask[op])]*/

	jmp	L_dolen



ALIGN 4

L_test_for_second_level_dist:

	test	al, 64

	jnz	L_invalid_distance_code ; /* if ((op & 64) != 0) */



	xor	eax, eax

	inc	eax

	shl	eax, cl

	dec	eax

	and	eax, edx         ; /* eax &= hold */

	add	eax, r15d        ; /* eax += dist */

	mov	eax, [r11+rax*4] ; /* eax = dcode[val+(hold&mask[op])]*/

	jmp	L_dodist



ALIGN 4

L_clip_window:

	mov	ecx, eax         ; /* ecx = nbytes */

	mov	eax, [rsp+92]     ; /* eax = wsize, prepare for dist cmp */

	neg	ecx                ; /* nbytes = -nbytes */



	cmp	eax, r15d

	jb	L_invalid_distance_too_far ; /* if (dist > wsize) */



	add	ecx, r15d         ; /* nbytes = dist - nbytes */

	cmp	dword ptr [rsp+96], 0

	jne	L_wrap_around_window ; /* if (write != 0) */



	mov	rsi, [rsp+56]     ; /* from  = window */

	sub	eax, ecx         ; /* eax  -= nbytes */

	add	rsi, rax         ; /* from += wsize - nbytes */



	mov	eax, r14d        ; /* eax = len */

	cmp	r14d, ecx

	jbe	L_do_copy           ; /* if (nbytes >= len) */



	sub	eax, ecx         ; /* eax -= nbytes */

	rep     movsb

	mov	rsi, rdi

	sub	rsi, r15         ; /* from = &out[ -dist ] */

	jmp	L_do_copy



ALIGN 4

L_wrap_around_window:

	mov	eax, [rsp+96]     ; /* eax = write */

	cmp	ecx, eax

	jbe	L_contiguous_in_window ; /* if (write >= nbytes) */



	mov	esi, [rsp+92]     ; /* from  = wsize */

	add	rsi, [rsp+56]     ; /* from += window */

	add	rsi, rax         ; /* from += write */

	sub	rsi, rcx         ; /* from -= nbytes */

	sub	ecx, eax         ; /* nbytes -= write */



	mov	eax, r14d        ; /* eax = len */

	cmp	eax, ecx

	jbe	L_do_copy           ; /* if (nbytes >= len) */



	sub	eax, ecx         ; /* len -= nbytes */

	rep     movsb

	mov	rsi, [rsp+56]     ; /* from = window */

	mov	ecx, [rsp+96]     ; /* nbytes = write */

	cmp	eax, ecx

	jbe	L_do_copy           ; /* if (nbytes >= len) */



	sub	eax, ecx         ; /* len -= nbytes */

	rep     movsb

	mov	rsi, rdi

	sub	rsi, r15         ; /* from = out - dist */

	jmp	L_do_copy



ALIGN 4

L_contiguous_in_window:

	mov	rsi, [rsp+56]     ; /* rsi = window */

	add	rsi, rax

	sub	rsi, rcx         ; /* from += write - nbytes */



	mov	eax, r14d        ; /* eax = len */

	cmp	eax, ecx

	jbe	L_do_copy           ; /* if (nbytes >= len) */



	sub	eax, ecx         ; /* len -= nbytes */

	rep     movsb

	mov	rsi, rdi

	sub	rsi, r15         ; /* from = out - dist */

	jmp	L_do_copy           ; /* if (nbytes >= len) */



ALIGN 4

L_do_copy:

	mov	ecx, eax         ; /* ecx = len */

	rep     movsb



	mov	rsi, r8          ; /* move in back to %esi, toss from */

	jmp	L_while_test



L_test_for_end_of_block:

	test	al, 32

	jz	L_invalid_literal_length_code

	mov	dword ptr [rsp+116], 1

	jmp	L_break_loop_with_status



L_invalid_literal_length_code:

	mov	dword ptr [rsp+116], 2

	jmp	L_break_loop_with_status



L_invalid_distance_code:

	mov	dword ptr [rsp+116], 3

	jmp	L_break_loop_with_status



L_invalid_distance_too_far:

	mov	dword ptr [rsp+116], 4

	jmp	L_break_loop_with_status



L_break_loop:

	mov	dword ptr [rsp+116], 0



L_break_loop_with_status:

; /* put in, out, bits, and hold back into ar and pop esp */

	mov	[rsp+16], rsi     ; /* in */

	mov	[rsp+32], rdi     ; /* out */

	mov	[rsp+88], ebx     ; /* bits */

	mov	[rsp+80], rdx     ; /* hold */



	mov	rax, [rsp]       ; /* restore rbp and rsp */

	mov	rbp, [rsp+8]

	mov	rsp, rax







	mov rsi,[rsp-8]

	mov rdi,[rsp-16]

	mov r12,[rsp-24]

	mov r13,[rsp-32]

	mov r14,[rsp-40]

	mov r15,[rsp-48]

	mov rbx,[rsp-56]

	

    ret 0

;          :

;          : "m" (ar)

;          : "memory", "%rax", "%rbx", "%rcx", "%rdx", "%rsi", "%rdi",

;            "%r8", "%r9", "%r10", "%r11", "%r12", "%r13", "%r14", "%r15"

;    );



inffas8664fnc 	ENDP

;_TEXT	ENDS

END

