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Amiga ACS 1998 #6
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tmap_skv.asm
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Assembly Source File
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1998-06-08
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9KB
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334 lines
;THE COMPUTER CODE CONTAINED HEREIN IS THE SOLE PROPERTY OF PARALLAX
;SOFTWARE CORPORATION ("PARALLAX"). PARALLAX, IN DISTRIBUTING THE CODE TO
;END-USERS, AND SUBJECT TO ALL OF THE TERMS AND CONDITIONS HEREIN, GRANTS A
;ROYALTY-FREE, PERPETUAL LICENSE TO SUCH END-USERS FOR USE BY SUCH END-USERS
;IN USING, DISPLAYING, AND CREATING DERIVATIVE WORKS THEREOF, SO LONG AS
;SUCH USE, DISPLAY OR CREATION IS FOR NON-COMMERCIAL, ROYALTY OR REVENUE
;FREE PURPOSES. IN NO EVENT SHALL THE END-USER USE THE COMPUTER CODE
;CONTAINED HEREIN FOR REVENUE-BEARING PURPOSES. THE END-USER UNDERSTANDS
;AND AGREES TO THE TERMS HEREIN AND ACCEPTS THE SAME BY USE OF THIS FILE.
;COPYRIGHT 1993-1998 PARALLAX SOFTWARE CORPORATION. ALL RIGHTS RESERVED.
;
; $Source: f:/miner/source/texmap/rcs/tmap_skv.asm $
; $Revision: 1.5 $
; $Author: mike $
; $Date: 1994/11/30 00:57:03 $
;
; Vertical scanner for sky bitmap rendering.
;
; $Log: tmap_skv.asm $
; Revision 1.5 1994/11/30 00:57:03 mike
; optimization.
;
; Revision 1.4 1994/11/12 16:41:13 mike
; jae -> ja.
;
; Revision 1.3 1994/05/24 11:03:12 mike
; Make work for any sized (power of 2) bitmap.
;
; Revision 1.2 1994/01/31 15:42:14 mike
; Vertical scanning sky texture mapper (in inner loop).
;
; Revision 1.1 1994/01/30 14:10:55 mike
; Initial revision
;
;
DEBUG_ON = 1
.386
option oldstructs
.nolist
include psmacros.inc
.list
public asm_tmap_scanline_lin_sky_v_, asm_tmap_scanline_lin_v_
include tmap_inc.asm
sky_width_log_2 equ 10
sky_height_log_2 equ 7
width_log_2 equ 6
height_log_2 equ 6
_DATA SEGMENT DWORD PUBLIC USE32 'DATA'
extd _fx_u
extd _fx_v
extd _fx_du_dx
extd _fx_dv_dx
extd _fx_y
extd _fx_xleft
extd _fx_xright
extd _pixptr
extd _x
extd _loop_count
_DATA ENDS
DGROUP GROUP _DATA
_TEXT SEGMENT PARA PUBLIC USE32 'CODE'
ASSUME DS:_DATA
ASSUME CS:_TEXT
; --------------------------------------------------------------------------------------------------
; Enter:
; _xleft fixed point left x coordinate
; _xright fixed point right x coordinate
; _y fixed point y coordinate
; _pixptr address of source pixel map
; _u fixed point initial u coordinate
; _v fixed point initial v coordinate
; _du_dx fixed point du/dx
; _dv_dx fixed point dv/dx
; for (x = (int) xleft; x <= (int) xright; x++) {
; _setcolor(read_pixel_from_tmap(srcb,((int) (u/z)) & 63,((int) (v/z)) & 63));
; _setpixel(x,y);
;
; u += du_dx;
; v += dv_dx;
; z += dz_dx;
; }
align 4
asm_tmap_scanline_lin_sky_v_:
pusha
; Setup for loop: _loop_count iterations = (int) xright - (int) xleft
; esi source pixel pointer = pixptr
; edi initial row pointer = y*320+x
; set esi = pointer to start of texture map data
mov esi,_pixptr
; set edi = address of first pixel to modify
mov edi,_fx_xleft
sar edi,16
jns edi_ok
sub edi,edi
edi_ok:
cmp edi,_window_bottom
ja _none_to_do
imul edi,_bytes_per_row
add edi,_fx_y
add edi,write_buffer
; set _loop_count = # of iterations
mov eax,_fx_xright
sar eax,16
mov ebx,_fx_xleft
sar ebx,16
sub eax,ebx
js _none_to_do
cmp eax,_window_height
jbe _ok_to_do
mov eax,_window_height
_ok_to_do:
mov _loop_count,eax
; edi destination pixel pointer
mov ebx,_fx_u
mov ecx,_fx_du_dx
mov edx,_fx_dv_dx
mov ebp,_fx_v
shl ebx,16-sky_width_log_2
shl ebp,16-sky_height_log_2
shl edx,16-sky_height_log_2
shl ecx,16-sky_width_log_2
; eax work
; ebx u
; ecx du_dx
; edx dv_dx
; ebp v
; esi read address
; edi write address
_size = (_end1 - _start1)/num_iters
mov eax,num_iters-1
sub eax,_loop_count
jns j_eax_ok1
inc eax ; sort of a hack, but we can get -1 here and want to be graceful
jns j_eax_ok1 ; if we jump, we had -1, which is kind of ok, if not, we int 3
int 3 ; oops, going to jump behind _start1, very bad...
sub eax,eax ; ok to continue
j_eax_ok1: imul eax,eax,dword ptr _size
add eax,offset _start1
jmp eax
align 4
_start1:
; "OPTIMIZATIONS" maybe not worth making
; Getting rid of the esi from the mov al,[esi+eax] instruction.
; This would require moving into eax at the top of the loop, rather than doing the sub eax,eax.
; You would have to align your bitmaps so that the two shlds would create the proper base address.
; In other words, your bitmap data would have to begin at 4096x (for 64x64 bitmaps).
; I did timings without converting the sub to a mov eax,esi and setting esi to the proper value.
; There was a speedup of about 1% to 1.5% without converting the sub to a mov.
; Getting rid of the edi by doing a mov nnnn[edi],al instead of mov [edi],al.
; The problem with this is you would have a dword offset for nnnn. My timings indicate it is slower. (I think.)
; Combining u,v and du,dv into single longwords.
; The problem with this is you then must do a 16 bit operation to extract them, and you don't have enough
; instructions to separate a destination operand from being used by the next instruction. It shaves out one
; register instruction (an add reg,reg), but adds a 16 bit operation, and the setup is more complicated.
; usage:
; eax work
; ebx u coordinate
; ecx delta u
; edx delta v
; ebp v coordinate
; esi pointer to source bitmap
; edi write address
rept num_iters
mov eax,ebp ; clear for
add ebp,edx ; update v coordinate
shr eax,32-sky_height_log_2 ; shift in v coordinate
shld eax,ebx,sky_width_log_2 ; shift in u coordinate while shifting up v coordinate
add ebx,ecx ; update u coordinate
mov al,[esi+eax] ; get pixel from source bitmap
mov [edi],al
add edi,_bytes_per_row
endm
_end1:
_none_to_do: popa
ret
; --------------------------------------------------------------------------------------------------------------------------------
align 4
asm_tmap_scanline_lin_v_:
pusha
; Setup for loop: _loop_count iterations = (int) xright - (int) xleft
; esi source pixel pointer = pixptr
; edi initial row pointer = y*320+x
; set esi = pointer to start of texture map data
mov esi,_pixptr
; set edi = address of first pixel to modify
mov edi,_fx_xleft
sar edi,16
jns edi_ok_a
sub edi,edi
edi_ok_a:
cmp edi,_window_bottom
ja _none_to_do_a
imul edi,_bytes_per_row
add edi,_fx_y
add edi,write_buffer
; set _loop_count = # of iterations
mov eax,_fx_xright
sar eax,16
mov ebx,_fx_xleft
sar ebx,16
sub eax,ebx
js _none_to_do_a
cmp eax,_window_height
jbe _ok_to_do_a
mov eax,_window_height
_ok_to_do_a:
mov _loop_count,eax
; edi destination pixel pointer
mov ebx,_fx_u
mov ecx,_fx_du_dx
mov edx,_fx_dv_dx
mov ebp,_fx_v
shl ebx,16-width_log_2
shl ebp,16-height_log_2
shl edx,16-height_log_2
shl ecx,16-width_log_2
; eax work
; ebx u
; ecx du_dx
; edx dv_dx
; ebp v
; esi read address
; edi write address
_size_a = (_end1_a - _start1_a)/num_iters
mov eax,num_iters-1
sub eax,_loop_count
jns j_eax_ok1_a
inc eax ; sort of a hack, but we can get -1 here and want to be graceful
jns j_eax_ok1_a ; if we jump, we had -1, which is kind of ok, if not, we int 3
int 3 ; oops, going to jump behind _start1, very bad...
sub eax,eax ; ok to continue
j_eax_ok1_a: imul eax,eax,dword ptr _size_a
add eax,offset _start1_a
jmp eax
align 4
_start1_a:
; "OPTIMIZATIONS" maybe not worth making
; Getting rid of the esi from the mov al,[esi+eax] instruction.
; This would require moving into eax at the top of the loop, rather than doing the sub eax,eax.
; You would have to align your bitmaps so that the two shlds would create the proper base address.
; In other words, your bitmap data would have to begin at 4096x (for 64x64 bitmaps).
; I did timings without converting the sub to a mov eax,esi and setting esi to the proper value.
; There was a speedup of about 1% to 1.5% without converting the sub to a mov.
; Getting rid of the edi by doing a mov nnnn[edi],al instead of mov [edi],al.
; The problem with this is you would have a dword offset for nnnn. My timings indicate it is slower. (I think.)
; Combining u,v and du,dv into single longwords.
; The problem with this is you then must do a 16 bit operation to extract them, and you don't have enough
; instructions to separate a destination operand from being used by the next instruction. It shaves out one
; register instruction (an add reg,reg), but adds a 16 bit operation, and the setup is more complicated.
; usage:
; eax work
; ebx u coordinate
; ecx delta u
; edx delta v
; ebp v coordinate
; esi pointer to source bitmap
; edi write address
rept num_iters
mov eax,ebp ; clear for
add ebp,edx ; update v coordinate
shr eax,32-height_log_2 ; shift in v coordinate
shld eax,ebx,width_log_2 ; shift in u coordinate while shifting up v coordinate
add ebx,ecx ; update u coordinate
mov al,[esi+eax] ; get pixel from source bitmap
mov [edi],al
add edi,_bytes_per_row
endm
_end1_a:
_none_to_do_a: popa
ret
_TEXT ends
end