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ReC98
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[Decompilation] [th01] GDC-powered graphics layer scrolling 

Surprise, it's the (terribly suboptimal) setgsta() example function
from the PC-9801 Programmers' Bible! 100% identical, so ZUN must have
read that book as well.
Used for screen shaking effects, as well as the scrolling backgrounds
at the start of the Final Boss stages.

Completes P0095, funded by Yanga.
This commit is contained in:
nmlgc 2020-05-31 14:36:10 +02:00
parent ec478666de
commit 8ddb77801d
6 changed files with 132 additions and 222 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
Makefile.mak
View File

@ -59,7 +59,7 @@ bin\th01\op.exe: bin\piloadc.obj bin\th01\op.obj th01\op_01.cpp th01\op_02.c th0
$**
|
bin\th01\reiiden.exe: bin\piloadc.obj bin\th01\reiiden.obj th01\main_01.cpp th01\main_02.c th01\main_03.c th01\main_04.c th01\main_05.c th01\main_06.cpp th01\main_07.cpp th01\main_08.cpp th01\main_12.c th01\main_13.c th01\main_14.c th01\main_16.c th01\main_19.cpp th01\main_25.cpp
bin\th01\reiiden.exe: bin\piloadc.obj bin\th01\reiiden.obj th01\main_01.cpp th01\main_02.c th01\main_03.c th01\main_04.c th01\main_05.c th01\main_06.cpp th01\main_07.cpp th01\main_08.cpp th01\main_12.c th01\main_13.cpp th01\main_13_.c th01\main_14.c th01\main_16.c th01\main_19.cpp th01\main_25.cpp
$(CC) $(CFLAGS) -ml -3 -DGAME=1 -DBINARY='M' -nbin\th01\ -eREIIDEN.EXE @&&|
$**
|

44
th01/hardware/scrollup.cpp Normal file
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@ -0,0 +1,44 @@
static const int GDC_ROW_SIZE = (ROW_SIZE / 2);
// Actually taken straight from the setgsta() example function from the
// PC-9801 Programmers' Bible, p. 150.
void z_vsync_wait_and_scrollup(int line_on_top)
{
line_on_top %= RES_Y;
int16_t dp1sta = (line_on_top * GDC_ROW_SIZE);
// Line counts start at the 5th bit of the parameter
int16_t dp1lin = ((RES_Y - line_on_top) << 4);
int16_t dp2sta = (0 * GDC_ROW_SIZE);
int16_t dp2lin = (line_on_top << 4);
// Display address increment time; depends on the GDC clock frequency
int im;
if((peekb(0, 0x54D) & 4) == 0) { // GDC clock == 2.5 MHz?
im = 0;
} else {
im = (1 << 6); // 6th bit inside the parameter
}
// Wait until VSYNC
while( (inportb(0xA0) & 0x20) != 0 );
while( (inportb(0xA0) & 0x20) == 0 );
// Wait until the graphics GDC's command FIFO is empty
while( (inportb(0xA0) & 0x04) == 0 );
// Graphics GDC SCROLL command
// (see PC-9801 Programmers' Bible, p. 143)
// ---------------------------
// 7 = SCROLL, 0 = starting regularly with the first parameter
outport(0xA2, 0x70);
// Display partition #1
outportb(0xA0, (dp1sta % 0x100));
outportb(0xA0, (dp1sta / 0x100));
outportb(0xA0, (dp1lin % 0x100));
outportb(0xA0, ((dp1lin / 0x100) + im));
// Display partition #2
outportb(0xA0, (dp2sta % 0x100));
outportb(0xA0, (dp2sta / 0x100));
outportb(0xA0, (dp2lin % 0x100));
outportb(0xA0, ((dp2lin / 0x100) + im));
// ---------------------------
}

4
th01/hardware/scrollup.hpp Normal file
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@ -0,0 +1,4 @@
// Waits until VSync, then sets the GDC's hardware scroll registers so that
// the given line will appear at the top of the screen for all subsequent
// frames.
void z_vsync_wait_and_scrollup(int line_on_top);

14
th01/main_13.cpp Normal file
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@ -0,0 +1,14 @@
/* ReC98
* -----
* 1st part of code segment #13 of TH01's REIIDEN.EXE
*/
extern "C" {
#include <dos.h>
#include "platform.h"
#include "pc98.h"
#include "th01/hardware/scrollup.cpp"
}

2
th01/main_13.c → th01/main_13_.c
View File

@ -1,6 +1,6 @@
/* ReC98
* -----
* Code segment #13 of TH01's REIIDEN.EXE
* 2nd part of code segment #13 of TH01's REIIDEN.EXE
*/
#include "th01/th01.h"

288
th01_reiiden.asm
View File

@ -65,6 +65,7 @@ include th01/th01.inc
extern _vsprintf:proc
main_01 group main_01_TEXT, main_01__TEXT
main_13 group main_13_TEXT, main_13__TEXT
main_19 group main_19_TEXT, main_19__TEXT
main_25 group main_25_TEXT, main_25__TEXT
@ -1291,7 +1292,7 @@ loc_C1D0:
idiv bx
or dx, dx
jnz short loc_C1E2
push 188h
push (RES_Y - 8)
jmp short loc_C214
; ---------------------------------------------------------------------------
@ -1308,7 +1309,7 @@ loc_C1E2:
idiv bx
cmp dx, 8
jnz short loc_C203
push 180h
push (RES_Y - 16)
jmp short loc_C214
; ---------------------------------------------------------------------------
@ -1321,10 +1322,10 @@ loc_C203:
jnz short loc_C21C
loc_C211:
push 190h
push RES_Y
loc_C214:
call sub_11738
call _z_vsync_wait_and_scrollup
pop cx
jmp short loc_C235
; ---------------------------------------------------------------------------
@ -1512,8 +1513,7 @@ loc_C3E7:
loc_C3EE:
cmp [bp+arg_0], 8Ch
jnz short loc_C42E
push 0
call sub_11738
call _z_vsync_wait_and_scrollup stdcall, 0
pop cx
push 1
call _graph_accesspage_func
@ -2604,10 +2604,9 @@ loc_CEE9:
cwd
idiv bx
shl dx, 3
mov ax, 190h
mov ax, RES_Y
sub ax, dx
push ax
call sub_11738
call _z_vsync_wait_and_scrollup stdcall, ax
pop cx
xor si, si
jmp short loc_CF31
@ -2739,8 +2738,7 @@ loc_CFF8:
loc_D00D:
cmp di, 10h
jl loc_CEE9
push 0
call sub_11738
call _z_vsync_wait_and_scrollup stdcall, 0
pop cx
mov al, byte_36C14
mov _bombs, al
@ -4356,8 +4354,7 @@ loc_DE72:
cmp _done, 0
jz loc_DC64
mov byte_34A47, 0
push 0
call sub_11738
call _z_vsync_wait_and_scrollup stdcall, 0
pop cx
les bx, _resident
mov eax, _rand
@ -5279,136 +5276,14 @@ main_12_TEXT ends
; Segment type: Pure code
main_13_TEXT segment byte public 'CODE' use16
assume cs:main_13_TEXT
main_13_TEXT ends
main_13__TEXT segment byte public 'CODE' use16
assume cs:main_13
;org 8
assume es:nothing, ss:nothing, ds:_DATA, fs:nothing, gs:nothing
; =============== S U B R O U T I N E =======================================
; Attributes: bp-based frame
sub_11738 proc far
var_6 = word ptr -6
var_4 = word ptr -4
var_2 = word ptr -2
arg_0 = word ptr 6
enter 6, 0
push si
push di
mov cx, [bp+arg_0]
mov bx, 190h
mov ax, cx
cwd
idiv bx
mov cx, dx
mov ax, cx
imul ax, 28h
mov si, ax
mov ax, 190h
sub ax, cx
shl ax, 4
mov di, ax
mov [bp+var_2], 0
mov ax, cx
shl ax, 4
mov [bp+var_4], ax
xor ax, ax
mov es, ax
test byte ptr es:[054Dh], 4
jnz short loc_1177C
mov [bp+var_6], 0
jmp short loc_11781
; ---------------------------------------------------------------------------
loc_1177C:
mov [bp+var_6], 40h
loc_11781:
mov dx, 0A0h
in al, dx ; PIC 2 same as 0020 for PIC 1
test al, 20h
jnz short loc_11781
loc_11789:
mov dx, 0A0h
in al, dx ; PIC 2 same as 0020 for PIC 1
test al, 20h
jz short loc_11789
loc_11791:
mov dx, 0A0h
in al, dx ; PIC 2 same as 0020 for PIC 1
test al, 4
jz short loc_11791
mov dx, 0A2h ; '¢'
mov ax, 70h ; 'p'
out dx, ax
mov ax, si
mov bx, 100h
cwd
idiv bx
push dx
mov dx, 0A0h
pop ax
out dx, al ; PIC 2 same as 0020 for PIC 1
mov ax, si
mov bx, 100h
cwd
idiv bx
mov dx, 0A0h
out dx, al ; PIC 2 same as 0020 for PIC 1
mov ax, di
mov bx, 100h
cwd
idiv bx
push dx
mov dx, 0A0h
pop ax
out dx, al ; PIC 2 same as 0020 for PIC 1
mov ax, di
mov bx, 100h
cwd
idiv bx
add al, byte ptr [bp+var_6]
mov dx, 0A0h
out dx, al ; PIC 2 same as 0020 for PIC 1
mov ax, [bp+var_2]
mov bx, 100h
cwd
idiv bx
push dx
mov dx, 0A0h
pop ax
out dx, al ; PIC 2 same as 0020 for PIC 1
mov ax, [bp+var_2]
mov bx, 100h
cwd
idiv bx
mov dx, 0A0h
out dx, al ; PIC 2 same as 0020 for PIC 1
mov ax, [bp+var_4]
mov bx, 100h
cwd
idiv bx
push dx
mov dx, 0A0h
pop ax
out dx, al ; PIC 2 same as 0020 for PIC 1
mov ax, [bp+var_4]
mov bx, 100h
cwd
idiv bx
add al, byte ptr [bp+var_6]
mov dx, 0A0h
out dx, al ; PIC 2 same as 0020 for PIC 1
pop di
pop si
leave
retf
sub_11738 endp
extern _z_vsync_wait_and_scrollup:proc
; =============== S U B R O U T I N E =======================================
@ -5917,7 +5792,7 @@ sub_11A94 endp
extern _graph_2xscale_byterect_1_to_0_sl:proc
extern _graph_copy_hline_mask_1_to_0:proc
extern _egc_copy_wave_1_to_0:proc
main_13_TEXT ends
main_13__TEXT ends
; ===========================================================================
@ -6409,8 +6284,7 @@ var_2 = word ptr -2
push si
push di
mov [bp+var_8], 0
push 0
call sub_11738
call _z_vsync_wait_and_scrollup stdcall, 0
pop cx
mov ax, point_3982A.y
add ax, 48
@ -6780,8 +6654,7 @@ var_2 = word ptr -2
push si
push di
mov [bp+var_8], 0
push 0
call sub_11738
call _z_vsync_wait_and_scrollup stdcall, 0
pop cx
mov ax, point_36C28.y
add ax, 16
@ -19884,10 +19757,9 @@ loc_1AE65:
cwd
idiv bx
shl dx, 3
mov ax, 190h
mov ax, RES_Y
sub ax, dx
push ax
call sub_11738
call _z_vsync_wait_and_scrollup stdcall, ax
pop cx
push 2
call _frame_delay
@ -19895,10 +19767,9 @@ loc_1AE65:
inc si
loc_1AE85:
cmp si, 10h
cmp si, 16
jl short loc_1AE65
push 0
call sub_11738
call _z_vsync_wait_and_scrollup stdcall, 0
pop cx
push (48 shl 16) or 48
push 352
@ -40798,10 +40669,9 @@ loc_26A94:
cwd
idiv bx
add dx, dx
mov ax, 190h
mov ax, RES_Y
sub ax, dx
push ax
call sub_11738
call _z_vsync_wait_and_scrollup stdcall, ax
pop cx
loc_26ABF:
@ -40825,8 +40695,7 @@ loc_26ABF:
call _graph_accesspage_func
push 2
call sub_24EC2
push 190h
call sub_11738
call _z_vsync_wait_and_scrollup stdcall, RES_Y
add sp, 0Ah
mov word_3A6CA, 0
mov ax, 1
@ -40970,10 +40839,9 @@ loc_26C11:
cwd
idiv bx
add dx, dx
mov ax, 190h
mov ax, RES_Y
sub ax, dx
push ax
call sub_11738
call _z_vsync_wait_and_scrollup stdcall, ax
pop cx
loc_26C3C:
@ -41034,8 +40902,7 @@ loc_26C85:
push ds
push offset point_3985C
call sub_1689D
push 190h
call sub_11738
call _z_vsync_wait_and_scrollup stdcall, RES_Y
add sp, 24h
mov word_3A6CA, 0
xor ax, ax
@ -43779,13 +43646,12 @@ sub_2869E proc far
add sp, 16h
call _mdrv2_bgm_play
call text_fillca pascal, (' ' shl 16) + TX_WHITE
mov si, 18Fh
mov si, (RES_Y - 1)
jmp short loc_2871C
; ---------------------------------------------------------------------------
loc_28703:
push si
call sub_11738
call _z_vsync_wait_and_scrollup stdcall, si
push 1
push si
call sub_11816
@ -43797,8 +43663,7 @@ loc_28703:
loc_2871C:
or si, si
jge short loc_28703
push 0
call sub_11738
call _z_vsync_wait_and_scrollup stdcall, 0
push 1
call _graph_accesspage_func
call _grp_put_palette_show stdcall, large [off_35DAB]
@ -46281,8 +46146,7 @@ loc_29D0E:
mov word_3A6CA, 31h ; '1'
cmp word_3AC60, 3
jl short loc_29D85
push 0
call sub_11738
call _z_vsync_wait_and_scrollup stdcall, 0
push 1
call _graph_accesspage_func
mov bx, [bp+arg_0]
@ -47413,7 +47277,7 @@ sub_2A896 proc near
idiv bx
or dx, dx
jnz short loc_2A8B2
push 18Ch
push (RES_Y - 4)
jmp short loc_2A8C3
; ---------------------------------------------------------------------------
@ -47424,10 +47288,10 @@ loc_2A8B2:
idiv bx
cmp dx, 4
jnz short loc_2A8C9
push 194h
push (RES_Y + 4)
loc_2A8C3:
call sub_11738
call _z_vsync_wait_and_scrollup
pop cx
loc_2A8C9:
@ -47447,8 +47311,7 @@ loc_2A8C9:
loc_2A8E0:
cmp word_3A6CA, 32h ; '2'
jnz short loc_2A8F5
push 0
call sub_11738
call _z_vsync_wait_and_scrollup stdcall, 0
pop cx
mov word_3A6CA, 0
@ -50750,8 +50613,7 @@ loc_2C949:
or dx, dx
jnz short loc_2C980
call _z_palette_set_show c, large (0Fh shl 16) or 0Fh, large (0Fh shl 16) or 0Fh
push 1A0h
call sub_11738
call _z_vsync_wait_and_scrollup stdcall, (RES_Y + 16)
pop cx
loc_2C980:
@ -50762,8 +50624,7 @@ loc_2C980:
cmp dx, 1
jnz short loc_2C99C
call sub_232D3
push 182h
call sub_11738
call _z_vsync_wait_and_scrollup stdcall, (RES_Y - 14)
pop cx
loc_2C99C:
@ -50781,8 +50642,7 @@ loc_2C9B1:
cmp word_3A6CA, 0C8h ; '?'
jnz short loc_2C9C6
call sub_232D3
push 0
call sub_11738
call _z_vsync_wait_and_scrollup stdcall, 0
pop cx
loc_2C9C6:
@ -50820,8 +50680,7 @@ loc_2C9DA:
mov byte_34A49, 1
call sub_190D6
call sub_1889C
push 0
call sub_11738
call _z_vsync_wait_and_scrollup stdcall, 0
pop cx
mov word_3A6CA, 0
mov word_3B433, 0
@ -51097,8 +50956,7 @@ loc_2CCDC:
idiv bx
or dx, dx
jnz short loc_2CCFF
push 1A0h
call sub_11738
call _z_vsync_wait_and_scrollup stdcall, (RES_Y + 16)
pop cx
loc_2CCFF:
@ -51108,8 +50966,7 @@ loc_2CCFF:
idiv bx
cmp dx, 1
jnz short loc_2CD16
push 182h
call sub_11738
call _z_vsync_wait_and_scrollup stdcall, (RES_Y - 14)
pop cx
loc_2CD16:
@ -51192,8 +51049,7 @@ loc_2CDA0:
; ---------------------------------------------------------------------------
loc_2CDAA:
push 0
call sub_11738
call _z_vsync_wait_and_scrollup stdcall, 0
pop cx
call sub_28908
xor si, si
@ -51436,18 +51292,17 @@ loc_2CF26:
add sp, 22h
mov word_398B8, 0
xor di, di
mov si, 20h ; ' '
mov si, 32
mov [bp+var_2], 0
mov [bp+var_8], 0
loc_2CFA2:
push di
call sub_11738
call _z_vsync_wait_and_scrollup stdcall, di
pop cx
add di, si
cmp [bp+var_2], 0
jnz short loc_2CFBA
cmp di, 64h ; 'd'
cmp di, ((RES_Y / 4) * 1)
jle short loc_2CFBA
inc [bp+var_2]
dec si
@ -51455,7 +51310,7 @@ loc_2CFA2:
loc_2CFBA:
cmp [bp+var_2], 1
jnz short loc_2CFCA
cmp di, 0C8h ; '?'
cmp di, ((RES_Y / 4) * 2)
jle short loc_2CFCA
inc [bp+var_2]
dec si
@ -51463,7 +51318,7 @@ loc_2CFBA:
loc_2CFCA:
cmp [bp+var_2], 2
jnz short loc_2CFDA
cmp di, 12Ch
cmp di, ((RES_Y / 4) * 3)
jle short loc_2CFDA
inc [bp+var_2]
dec si
@ -51471,11 +51326,11 @@ loc_2CFCA:
loc_2CFDA:
cmp [bp+var_2], 3
jnz short loc_2CFF0
cmp di, 190h
cmp di, RES_Y
jle short loc_2CFF0
mov [bp+var_2], 0
dec si
sub di, 190h
sub di, RES_Y
loc_2CFF0:
or si, si
@ -51542,8 +51397,7 @@ loc_2D06B:
; ---------------------------------------------------------------------------
loc_2D079:
push 0
call sub_11738
call _z_vsync_wait_and_scrollup stdcall, 0
call _grz_load_single stdcall, 0, offset aBoss8_grz, ds, 0 ; "boss8.grz"
call _grz_load_single stdcall, 1, offset aBoss8_grz, ds, 1 ; "boss8.grz"
call _grz_load_single stdcall, 2, offset aBoss8_grz, ds, 2 ; "boss8.grz"
@ -51565,10 +51419,9 @@ loc_2D0EC:
cwd
idiv bx
shl dx, 5
mov ax, 1A0h
mov ax, (RES_Y + 16)
sub ax, dx
push ax
call sub_11738
call _z_vsync_wait_and_scrollup stdcall, ax
pop cx
mov ax, si
mov bx, 8
@ -51587,22 +51440,21 @@ loc_2D117:
inc si
loc_2D120:
cmp si, 20h ; ' '
cmp si, 32
jl short loc_2D0EC
mov di, 190h
mov di, RES_Y
jmp short loc_2D145
; ---------------------------------------------------------------------------
loc_2D12A:
push di
call sub_11738
call _z_vsync_wait_and_scrollup stdcall, di
push 20h ; ' '
push di
call sub_11816
push 1
call _frame_delay
add sp, 8
sub di, 20h ; ' '
sub di, 32
loc_2D145:
or di, di
@ -51617,17 +51469,16 @@ loc_2D14D:
cwd
idiv bx
shl dx, 4
mov ax, 1A0h
mov ax, (RES_Y + 16)
sub ax, dx
push ax
call sub_11738
call _z_vsync_wait_and_scrollup stdcall, ax
push 1
call _frame_delay
add sp, 4
inc si
loc_2D16E:
cmp si, 20h ; ' '
cmp si, 32
jl short loc_2D14D
push 1Eh
call _frame_delay
@ -55745,11 +55596,10 @@ loc_2F9F9:
mov bx, 2
cwd
idiv bx
imul dx, -10h
mov ax, 198h
imul dx, -16
mov ax, (RES_Y + 8)
sub ax, dx
push ax
call sub_11738
call _z_vsync_wait_and_scrollup stdcall, ax
pop cx
cmp word_3A6CA, 40h
jg short loc_2FA23
@ -55858,17 +55708,16 @@ loc_2FADC:
cmp di, 19h
jl short loc_2FAC5
xor si, si
mov di, 20h ; ' '
mov di, 32
mov [bp+var_6], 0
loc_2FAEB:
push si
call sub_11738
call _z_vsync_wait_and_scrollup stdcall, si
pop cx
add si, di
cmp si, 190h
cmp si, RES_Y
jle short loc_2FAFE
sub si, 190h
sub si, RES_Y
loc_2FAFE:
cmp [bp+var_6], 96h
@ -56005,8 +55854,7 @@ loc_2FC0E:
; ---------------------------------------------------------------------------
loc_2FC1C:
push 0
call sub_11738
call _z_vsync_wait_and_scrollup stdcall, 0
pop cx
xor si, si
jmp short loc_2FC32