[C decompilation] [th01] VSync interrupt handler

Time to get back into this.

Makefile.mak

@@ -28,17 +28,17 @@ th05:: $(TH05:\=bin\th05\)
 bin\th01\zunsoft.com: th01\zunsoft.c
 	$(CC) $(CFLAGS) -mt -lt -nbin\th01\ $** masters.lib
 
-bin\th01\op.exe: bin\th01\op.obj th01\op_04.c th01\op_10.c th01\op_11.c th01\op_12.cpp
+bin\th01\op.exe: bin\th01\op.obj th01\op_03.c th01\op_04.c th01\op_10.c th01\op_11.c th01\op_12.cpp
 	$(CC) $(CFLAGS) -ml -3 -nbin\th01\ -eOP.EXE @&&|
 $**
 |
 
-bin\th01\reiiden.exe: bin\th01\reiiden.obj th01\main_04.c th01\main_12.c th01\main_13.c th01\main_14.c th01\main_16.c
+bin\th01\reiiden.exe: bin\th01\reiiden.obj th01\main_03.c th01\main_04.c th01\main_12.c th01\main_13.c th01\main_14.c th01\main_16.c
 	$(CC) $(CFLAGS) -ml -3 -nbin\th01\ -eREIIDEN.EXE @&&|
 $**
 |
 
-bin\th01\fuuin.exe: bin\th01\fuuin.obj th01\fuuin_06.c th01\fuuin_11.c th01\fuuin_12.c th01\fuuin_13.c
+bin\th01\fuuin.exe: bin\th01\fuuin.obj th01\fuuin_05.c th01\fuuin_06.c th01\fuuin_11.c th01\fuuin_12.c th01\fuuin_13.c
 	$(CC) $(CFLAGS) -ml -3 -nbin\th01\ -eFUUIN.EXE @&&|
 $**
 |

th01/fuuin_05.c

@@ -0,0 +1,7 @@
+/* ReC98
+ * -----
+ * Code segment #5 of TH01's FUUIN.EXE
+ */
+
+#include "th01/hardware/vsync.c"
+#include "th01/hardware/vsyncclr.c"

th01/hardware/vsync.c

@@ -0,0 +1,80 @@
+/* ReC98
+ * -----
+ * VSync interrupt handler
+ */
+
+#include "th01/th01.h"
+
+#pragma option -2
+#pragma warn -aus
+
+extern char vsync_initialized;
+extern int vsync_callback_is_set;
+
+extern int RES_X_HALF;
+extern int RES_Y_HALF;
+
+extern int vsync_frame;
+extern int vsync_unused;
+extern void interrupt (*vsync_callback_old)(void);
+extern void (*vsync_callback)(void);
+
+static void interrupt vsync_intfunc(void)
+{
+	int res_x_half = RES_X_HALF;
+	int res_y_half = RES_Y_HALF;
+	vsync_frame++;
+	vsync_unused++;
+	if(vsync_callback_is_set) {
+		vsync_callback();
+	}
+	OUTB(0x00, 0x20); // End of Interrupt
+	OUTB(0x64, 0); // VSync interrupt trigger
+}
+
+void vsync_init(void)
+{
+	if(vsync_initialized == 0) {
+		vsync_initialized = 1;
+		disable();
+		vsync_callback_old = getvect(0x0A);
+		setvect(0x0A, vsync_intfunc);
+
+		// Disable all interrupts from 0x08 to 0x0F except for 0x0A
+		OUTB(0x02, INPB(0x02) & 0xFB);
+
+		OUTB(0x64, 0); // VSync interrupt trigger
+		enable();
+	}
+}
+
+void vsync_exit(void)
+{
+	if(vsync_initialized == 1) {
+		vsync_initialized = 0;
+		disable();
+
+		// Reenable all interrupts from 0x08 to 0x0F except for 0x0A
+		OUTB(0x02, INPB(0x02) | 0x04);
+
+		setvect(0x0a, vsync_callback_old);
+		enable();
+	}
+}
+
+void z_vsync_wait(void)
+{
+	do {
+		_AL = INPB(0x60);
+	} while((_AL & 0x20) != 0);
+	do {
+		_AL = INPB(0x60);
+	} while((_AL & 0x20) == 0);
+}
+
+void vsync_callback_set(void (*vsync_callback_new)())
+{
+	vsync_callback_is_set = 0;
+	vsync_callback = vsync_callback_new;
+	vsync_callback_is_set = 1;
+}

th01/hardware/vsync[bss].asm

@@ -0,0 +1,5 @@
+public _vsync_frame, _vsync_unused, _vsync_callback_old, _vsync_callback
+_vsync_frame	dw ?
+_vsync_unused	dw ?
+_vsync_callback_old	dd ?
+_vsync_callback	dd ?

th01/hardware/vsync[data].asm

@@ -0,0 +1,46 @@
+public _vsync_initialized, _vsync_callback_is_set, _RES_X_HALF, _RES_Y_HALF
+_vsync_initialized	db 0
+_vsync_callback_is_set	dw 0
+	dd    7
+	dd    0
+_RES_X_HALF	dw 320
+_RES_Y_HALF	dw 200
+
+; Unused?
+	dw 0
+	dw 0
+	dw 639
+	dw 399
+	dw 0C000h
+	dw 0E000h
+	dw 0F000h
+	dw 0F800h
+	dw 0FC00h
+	dw 0FE00h
+	dw 0FF00h
+	dw 0FF80h
+	dw 0FFC0h
+	dw 0FFE0h
+	dw 0FE00h
+	dw 0EF00h
+	dw 0CF00h
+	dw 780h
+	dw 780h
+	dw 300h
+	dw 0
+	dw 4000h
+	dw 6000h
+	dw 7000h
+	dw 7800h
+	dw 7C00h
+	dw 7E00h
+	dw 7F00h
+	dw 7F80h
+	dw 7C00h
+	dw 6C00h
+	dw 4600h
+	dw 600h
+	dw 300h
+	dw 300h
+	dw 0
+	db 0

th01/hardware/vsyncclr.c

@@ -0,0 +1,12 @@
+/* ReC98
+ * -----
+ * VSync interrupt callback clear function. In REIIDEN.EXE, this function needs
+ * to be put into a segment separate from vsync.c.
+ */
+
+extern int vsync_callback_is_set;
+
+void vsync_callback_clear(void)
+{
+	vsync_callback_is_set = 0;
+}

th01/main_03.c

@@ -0,0 +1,6 @@
+/* ReC98
+ * -----
+ * Code segment #3 of TH01's REIIDEN.EXE
+ */
+
+#include "th01/hardware/vsync.c"

th01/main_04.c

@@ -3,4 +3,5 @@
  * Code segment #4 of TH01's REIIDEN.EXE
  */
 
+#include "th01/hardware/vsyncclr.c"
 #include "th01/ztext.c"

th01/op_03.c

@@ -0,0 +1,7 @@
+/* ReC98
+ * -----
+ * Code segment #3 of TH01's OP.EXE
+ */
+
+#include "th01/hardware/vsync.c"
+#include "th01/hardware/vsyncclr.c"