[Separate translation units] [th02] snd_determine_mode()

Perfectly decompilable with pseudo-registers. Why did I decide against
them in 2015?

Part of P0133, funded by [Anonymous].

Makefile.mak

@@ -78,17 +78,17 @@ bin\th02\zun_res.com: th02\zun_res1.c th02\zun_res2.c th02\zun_res3.c
 $**
 | masters.lib
 
-bin\th02\op.exe: th02\op_01.cpp bin\exit_dos.obj bin\th02\zunerror.obj bin\th02\grppsafx.obj bin\th02\op.obj th02\op_02_1.cpp bin\th02\pi_load.obj bin\th02\grp_rect.obj bin\frmdely2.obj th02\op_02_2.cpp bin\th02\snd_pmdr.obj bin\th02\snd_load.obj bin\th02\pi_put.obj bin\th02\snd_kaja.obj th02\op_02_3.cpp bin\th02\snd_se.obj bin\frmdely1.obj th02\op_03.cpp th02\op_04.cpp th02\op_05.cpp th02\op_06.cpp
+bin\th02\op.exe: th02\op_01.cpp bin\exit_dos.obj bin\th02\zunerror.obj bin\th02\grppsafx.obj bin\th02\op.obj th02\op_02_1.cpp bin\th02\pi_load.obj bin\th02\grp_rect.obj bin\frmdely2.obj th02\op_02_2.cpp bin\th02\snd_mode.obj bin\th02\snd_pmdr.obj bin\th02\snd_load.obj bin\th02\pi_put.obj bin\th02\snd_kaja.obj th02\op_02_3.cpp bin\th02\snd_se.obj bin\frmdely1.obj th02\op_03.cpp th02\op_04.cpp th02\op_05.cpp th02\op_06.cpp
 	$(CC) $(CFLAGS) -ml -Z -DGAME=2 -nbin\th02\ -eOP.EXE @&&|
 $**
 |
 
-bin\th02\main.exe: bin\th02\main.obj bin\th02\zunerror.obj th02\main02_1.cpp bin\th02\pi_load.obj bin\th02\vector.obj bin\frmdely1.obj th02\main02_2.cpp bin\th02\snd_pmdr.obj bin\th02\snd_dlyv.obj bin\th02\snd_load.obj th02\mptn_i.cpp bin\th02\initmain.obj bin\th02\pi_put.obj bin\th02\snd_kaja.obj bin\th02\snd_dlym.obj bin\th02\snd_se.obj th02\main_03.cpp
+bin\th02\main.exe: bin\th02\main.obj bin\th02\zunerror.obj th02\main02_1.cpp bin\th02\pi_load.obj bin\th02\vector.obj bin\frmdely1.obj th02\main02_2.cpp bin\th02\snd_mode.obj bin\th02\snd_pmdr.obj bin\th02\snd_dlyv.obj bin\th02\snd_load.obj th02\mptn_i.cpp bin\th02\initmain.obj bin\th02\pi_put.obj bin\th02\snd_kaja.obj bin\th02\snd_dlym.obj bin\th02\snd_se.obj th02\main_03.cpp
 	$(CC) $(CFLAGS) -ml -Z -DGAME=2 -nbin\th02\ -eMAIN.EXE @&&|
 $**
 |
 
-bin\th02\maine.exe: bin\th02\maine.obj bin\th02\grppsafx.obj th02\maine021.cpp bin\th02\pi_load.obj bin\frmdely1.obj th02\maine022.cpp bin\th02\snd_pmdr.obj bin\th02\snd_load.obj bin\th02\initmain.obj bin\th02\pi_put.obj bin\th02\snd_kaja.obj bin\th02\snd_dlym.obj th02\maine_03.c th02\maine_04.cpp th02\maine_05.cpp
+bin\th02\maine.exe: bin\th02\maine.obj bin\th02\grppsafx.obj th02\maine021.cpp bin\th02\pi_load.obj bin\frmdely1.obj th02\maine022.cpp bin\th02\snd_mode.obj bin\th02\snd_pmdr.obj bin\th02\snd_load.obj bin\th02\initmain.obj bin\th02\pi_put.obj bin\th02\snd_kaja.obj bin\th02\snd_dlym.obj th02\maine_03.c th02\maine_04.cpp th02\maine_05.cpp
 	$(CC) $(CFLAGS) -ml -3 -Z -DGAME=2 -nbin\th02\ -eMAINE.EXE @&&|
 $**
 |

th02/main02_2.cpp

@@ -18,5 +18,4 @@ extern "C" {
 #include "th02/hardware/input.c"
 #include "th02/exit.c"
 #include "th02/snd/mmd_res.c"
-#include "th02/snd/detmode.c"
 }

th02/maine022.cpp

@@ -21,5 +21,4 @@ extern const char pf_fn[] = PF_FN;
 #include "th02/hardware/input.c"
 #include "th02/exit.c"
 #include "th02/snd/mmd_res.c"
-#include "th02/snd/detmode.c"
 }

th02/op_02_2.cpp

@@ -29,5 +29,4 @@ const char pf_fn[] = PF_FN;
 #pragma codestring "\x00"
 
 #include "th02/snd/mmd_res.c"
-#include "th02/snd/detmode.c"
 }

th02/snd/detmode.c

@@ -1,16 +1,24 @@
-int snd_determine_mode(void)
-{
-	__asm	mov ah, PMD_GET_DRIVER_VERSION;
-	__asm	int PMD;
-	_BX = 0;
-	if(_AL != 0xFF) {
-		__asm	inc bx;
-		snd_fm_possible = 1;
-	} else {
-		__asm	mov bl, snd_midi_active;
-	}
-		__asm	mov snd_active, bl;
-	return _BX;
-}
-
-#pragma codestring "\x90"
+#pragma codeseg SHARED
+#pragma option -k-
+
+#include <dos.h>
+#include "platform.h"
+#include "libs/kaja/kaja.h"
+#include "th02/snd/snd.h"
+
+bool16 snd_determine_mode(void)
+{
+	_AH = PMD_GET_DRIVER_VERSION;
+	geninterrupt(PMD);
+	_BX = false;
+	if(_AL != 0xFF) {
+		_BX++;
+		snd_fm_possible = true;
+	} else {
+		_BL = snd_midi_active;
+	}
+	snd_active = _BL;
+	return _BX;
+}
+
+#pragma codestring "\x90"

th02/snd/snd.h

@@ -31,7 +31,11 @@ bool16 snd_pmd_resident(void);
 	int snd_mmd_resident(void);
 #endif
 
-int snd_determine_mode(void);
+// Checks whether an FM sound source is active, and sets [snd_fm_possible]
+// and [snd_active]. In the absence of an FM source, [snd_active] is set to
+// [snd_midi_active]. Returns the new value of [snd_active].
+bool16 snd_determine_mode(void);
+
 int16_t DEFCONV snd_kaja_interrupt(int16_t ax);
 #define snd_kaja_func(func, param) snd_kaja_interrupt((func) << 8 | (param))
 

th02/snd_mode.c

@@ -0,0 +1 @@
+#include "th02/snd/detmode.c"