kernel: allows syscalls to be called from fixed addresses

src/kernel/kernel.c

@@ -40,6 +40,9 @@ void *gint_stack_top = NULL;
 /* kinit(): Install and start gint */
 void kinit(void)
 {
+	/* Figure out which CASIOWIN API to use based on the OS type. */
+	gint_set_CASIOWIN_API(0);
+
 	#if GINT_HW_FX
 	/* On fx-9860G, VBR is loaded at the end of the user RAM. On SH4, the
 	   end of the user RAM hosts the stack, for which we leave 12 kB

src/kernel/kernel.h

@@ -18,4 +18,7 @@ void kinit(void);
 /* kquit(): Quit gint and give back control to the system */
 void kquit(void);
 
+/* Select the CASIOWIN API for syscalls. */
+void gint_set_CASIOWIN_API(int API);
+
 #endif /* GINT_CORE_KERNEL */

src/kernel/osmenu.c

@@ -122,11 +122,6 @@ void gint_osmenu_native(void)
 	}
 	#endif
 
-	/* Mysteriously crashes when coming back; might be useful another time
-	   instead of GetKeyWait()
-	int C=0x04, R=0x09;
-	__SpecialMatrixCodeProcessing(&C, &R); */
-
 	__osmenu_id = __Timer_Install(0, __osmenu_handler, 0 /* ms */);
 	if(__osmenu_id <= 0) return;
 	__Timer_Start(__osmenu_id);

src/kernel/syscalls.S

@@ -144,82 +144,107 @@ syscall_table:
 #endif /* GINT_OS_FX */
 
 #if GINT_OS_CG
+#define CASIOWIN_API_VERSIONS 2
+.global _gint_set_CASIOWIN_API
 
-/* Dynamic allocation */
+/* System for dynamically selecting between the syscall and fixed version of
+   each function based on the OS version.
+   @r0: Internal function ID (from table below) */
+_CASIOWIN_call:
+	mov	#(4*CASIOWIN_API_VERSIONS), r1
+	mulu.w	r0, r1
+	mov.l	3f, r0
+	mov.l	@r0, r2
+	sts	macl, r1
 
-___malloc:
-	syscall(0x1f44)
-___free:
-	syscall(0x1f42)
-___realloc:
-	syscall(0x1f46)
+	/* API version 0 is the normal syscall table */
+	tst	r2, r2
+	mova	.CASIOWIN_TABLE, r0
+	bt.s	1f
+	mov.l	@(r0, r1), r0
 
-/* BFile driver */
+	/* Other API versions are the direct calls */
+	jmp	@r0
+	nop
 
-_BFile_Remove:
-	syscall(0x1db4)
-_BFile_Rename:
-	syscall(0x1db3)
-_BFile_Create:
-	syscall(0x1dae)
-_BFile_Open:
-	mov #0, r6
-	syscall(0x1da3)
-_BFile_Close:
-	syscall(0x1da4)
-_BFile_Size:
-	syscall(0x1da6)
-_BFile_Seek:
-	syscall(0x1da9)
-_BFile_GetPos:
-	syscall(0x1dab)
-_BFile_Write:
-	syscall(0x1daf)
-_BFile_Read:
-	syscall(0x1dac)
-_BFile_FindFirst:
-	syscall(0x1db6)
-_BFile_FindNext:
-	syscall(0x1db8)
-_BFile_FindClose:
-	syscall(0x1dba)
+1:	mov.l	2f, r1
+	jmp	@r1
+	nop
 
-/* Return to menu */
+2:	.long	0x80020070
 
-___Timer_Install:
-	syscall(0x8d9)
-___Timer_Start:
-	syscall(0x8db)
-___Timer_Stop:
-	syscall(0x8dc)
-___Timer_Deinstall:
-	syscall(0x8da)
-___PutKeyCode:
-	syscall(0x12c6)
-___GetKeyWait:
-	syscall(0x12bf)
-___ClearKeyBuffer:
-	syscall(0x12c7)
-___GetVRAMAddress:
-	syscall(0x1e6)
-___ConfigureStatusArea:
-	syscall(0x2b7)
-___SetQuitHandler:
-	syscall(0x1e6e)
+_gint_set_CASIOWIN_API:
+	mov.l	3f, r0
+	rts
+	mov.l	r4, @r0
 
-.global ___SpecialMatrixCodeProcessing
-___SpecialMatrixCodeProcessing:
-	syscall(0x1e60)
+.balign 4
+3:	.long	.CASIOWIN_API
 
-/* Reset */
+.CASIOWIN_TABLE:
+	.long 0x1f44, 0x00000000  /* malloc */
+	.long 0x1f42, 0x00000000  /* free */
+	.long 0x1f46, 0x00000000  /* realloc */
+	.long 0x1db4, 0x00000000  /* BFile_Remove */
+	.long 0x1db3, 0x00000000  /* BFile_Rename */
+	.long 0x1dae, 0x00000000  /* BFile_Create */
+	.long 0x1da3, 0x00000000  /* BFile_Open */
+	.long 0x1da4, 0x00000000  /* BFile_Close */
+	.long 0x1da6, 0x00000000  /* BFile_Size */
+	.long 0x1da9, 0x00000000  /* BFile_Seek */
+	.long 0x1dab, 0x00000000  /* BFile_GetPos */
+	.long 0x1daf, 0x00000000  /* BFile_Write */
+	.long 0x1dac, 0x00000000  /* BFile_Read */
+	.long 0x1db6, 0x00000000  /* BFile_FindFirst */
+	.long 0x1db8, 0x00000000  /* BFile_FindNext */
+	.long 0x1dba, 0x00000000  /* BFile_FindClose */
+	.long 0x08d9, 0x00000000  /* Timer_Install */
+	.long 0x08db, 0x00000000  /* Timer_Start */
+	.long 0x08dc, 0x00000000  /* Timer_Stop */
+	.long 0x08da, 0x00000000  /* Timer_Deinstall */
+	.long 0x12c6, 0x00000000  /* PutKeyCode */
+	.long 0x12bf, 0x00000000  /* GetKeyWait */
+	.long 0x12c7, 0x00000000  /* ClearKeyBuffer */
+	.long 0x01e6, 0x00000000  /* GetVRAMAddress */
+	.long 0x02b7, 0x00000000  /* ConfigureStatusArea */
+	.long 0x1e6e, 0x00000000  /* SetQuitHandler */
+	.long 0x1839, 0x00000000  /* PowerOff */
+	.long 0x1187, 0x00000000  /* Reset */
 
-___PowerOff:
-	syscall(0x1839)
-___Reset:
-	syscall(0x1187)
+#define casiowin_call(id) bra _CASIOWIN_call; mov id, r0
 
-syscall_table:
-	.long	0x80020070
+___malloc:               casiowin_call(#0)
+___free:                 casiowin_call(#1)
+___realloc:              casiowin_call(#2)
+_BFile_Remove:           casiowin_call(#3)
+_BFile_Rename:           casiowin_call(#4)
+_BFile_Create:           casiowin_call(#5)
+_BFile_Open:             mov #0, r6; casiowin_call(#6)
+_BFile_Close:            casiowin_call(#7)
+_BFile_Size:             casiowin_call(#8)
+_BFile_Seek:             casiowin_call(#9)
+_BFile_GetPos:           casiowin_call(#10)
+_BFile_Write:            casiowin_call(#11)
+_BFile_Read:             casiowin_call(#12)
+_BFile_FindFirst:        casiowin_call(#13)
+_BFile_FindNext:         casiowin_call(#14)
+_BFile_FindClose:        casiowin_call(#15)
+___Timer_Install:        casiowin_call(#16)
+___Timer_Start:          casiowin_call(#17)
+___Timer_Stop:           casiowin_call(#18)
+___Timer_Deinstall:      casiowin_call(#19)
+___PutKeyCode:           casiowin_call(#20)
+___GetKeyWait:           casiowin_call(#21)
+___ClearKeyBuffer:       casiowin_call(#22)
+___GetVRAMAddress:       casiowin_call(#23)
+___ConfigureStatusArea:  casiowin_call(#24)
+___SetQuitHandler:       casiowin_call(#25)
+___PowerOff:             casiowin_call(#26)
+___Reset:                casiowin_call(#27)
+
+.data
+.CASIOWIN_API:
+	.long 0
 
 #endif /* GINT_OS_CG */