add system identification

Makefile

@@ -95,13 +95,15 @@ binaries: all
 	-mkdir $(BINDIR)
 	-cp kernel/boot.$(MACHINE) kernel/lunix.$(MACHINE) $(MODULES:%=kernel/modules/%) $(BINDIR)
 
-nintendodisc: nintendopackage
-	mkfds -# -i -b 4 lunix.fds pkg/kyodaku.bin pkg/ascii.bin pkg/reset.bin pkg/boot.bin pkg/lunix.bin pkg/sh.bin pkg/ls.bin pkg/cat.bin pkg/pwd.bin pkg/ps.bin pkg/hello.bin
+mesen: nintendodisc
 	# mesen label files
 	-rm ./lunix.mlb
 	sed -nE 's/#define\s+(\w+)\s+([0-9]+).*/\2 \1/p' ./include/zp.h | xargs printf 'R:%x:%s\n' >> ./lunix.mlb
 	sed -nE 's/#define\s+(\w+)\s+\$$(.*)/\1 \2/p' ./include/ksym.h | awk '{ $$2 = sprintf("%d","0x" $$2) - "0x6000"; printf("W:%x:%s\n", $$2, $$1) }' >> ./lunix.mlb
+	mono ~/.local/bin/Mesen.exe ./lunix.fds &
 
+nintendodisc: nintendopackage
+	mkfds -# -i -b 4 lunix.fds pkg/kyodaku.bin pkg/ascii.bin pkg/reset.bin pkg/boot.bin pkg/lunix.bin pkg/sh.bin pkg/ls.bin pkg/cat.bin pkg/pwd.bin pkg/ps.bin pkg/hello.bin
 
 nintendopackage: binaries
 	-mkdir pkg

include/system.h

@@ -140,10 +140,12 @@
 #define lk_modroot   SYSTEM_MEMORY+$ed    ;// root of linked list of modules (16bit)
 #define lk_consmax   SYSTEM_MEMORY+$ef    ;// absolute number of consoles
 #define lk_archtype  SYSTEM_MEMORY+$f0    ;// machine architecture
-#  define larchf_type     %00000011 ;// type of machine
+#  define larchf_type     %00000111 ;// type of machine
 #   define larch_c64       0
 #   define larch_c128      1
 #   define larch_atari     2
+#   define larch_nintendo  3
+#  define larchf_2a0x     %00001000 ;// flag for RP2A0x CPU (no decimal mode)
 #  define larchf_8500     %00010000 ;// flag for 85xx (not 65xx) CPU
 #  define larchf_pal      %00100000 ;// flag for PAL (not NTSC) video hardware
 #  define larchf_reu      %01000000 ;// flag for available REU hardware

kernel/bootstrap.s

@@ -402,6 +402,18 @@ noide64_txt:	.text "Kernel panic: IDE64 not detected",$0a
 	+
 #endif
 
+		;; use decimal mode to detect Ricoh 2A0x CPU.
+		sed
+		lda #$09
+		clc
+		adc #01
+		cmp $10
+		beq +
+		lda  lk_archtype
+		ora  #larchf_2a0x
+		sta  lk_archtype
+	+	cli
+
 		;; spawn init task		
 		lda  #0
 		sta  userzp
@@ -471,6 +483,8 @@ txt_c128:
 		.text "Commodore 128",0
 txt_atari:
 		.text "Atari",0
+txt_nintendo:
+		.text "Famicom/NES",0
 txt_pal:
 		.text " (PAL)",0
 txt_ntsc:
@@ -489,12 +503,16 @@ print_machine_type:
 		beq  ++
 		cmp  #larch_atari
 		beq  +++
-		bne  ++++
+		cmp  #larch_nintendo
+		beq  ++++
+		bne  +++++
 	+	ldy  #txt_c64-txt_c64
 		SKIP_WORD
 	+	ldy  #txt_c128-txt_c64
 		SKIP_WORD
 	+	ldy  #txt_atari-txt_c64
+		SKIP_WORD
+	+	ldy  #txt_nintendo-txt_c64
 		jsr  mout
 
 	+	lda  lk_archtype
@@ -510,7 +528,12 @@ print_machine_type:
 		bne  mout
 		ldy  #txt_60hz-txt_c64
 #else
+		; assume that frequency matches the video standard.
+		lda  lk_archtype
 		ldy  #txt_50hz-txt_c64
+		and  #larchf_pal
+		bne  mout
+		ldy  #txt_60hz-txt_c64
 #endif
 mout:		lda  txt_c64,y
 		beq  +

kernel/nintendo/irqinit.s

@@ -19,12 +19,23 @@
 		sta FDS_IRQ_CTRL
 
 		; configure the timer to generate an IRQ every 1/64 second.
+		lda lk_archtype
+		and #larchf_pal
+		bne +
+
 		; NES/Famicom (NTSC) CPU @ 1.789773 MHz
 		; 1789773 hz / 64 = 27965.203125
-		lda #<27965
-		sta FDS_TIMER_LO
-		lda #>27965
-		sta FDS_TIMER_HI
+		ldx #<27965
+		ldy #>27965
+		bne ++
+
+		; NES (PAL) CPU @ 1.662607 MHz
+		; 1789773 hz / 64 = 25978.234375
+	+	ldx #<25978
+		ldy #>25978
+
+	+	stx FDS_TIMER_LO
+		sty FDS_TIMER_HI
 
 		; enable timer IRQ and reload the timer after every interrupt.
 		lda #FDS_TIMER_CTRL_E | FDS_TIMER_CTRL_R

kernel/nintendo/reset.s

@@ -19,7 +19,43 @@ vblankwait1:
 		bpl vblankwait1
 
 		; We now have about 30,000 cycles to burn before the PPU stabilizes.
+		; we'll use it to identify our system.
+		ldy #0
 
 vblankwait2:
+		inx
+		bne noincy
+		iny
+noincy:
 		bit PPU_STATUS
 		bpl vblankwait2
+
+		; because of a hardware oversight, we might have missed a vblank flag.
+		; so we have to account for 1 or 2 vblanks.
+
+		; system      | cycles per | cycles per | 1 vblank | 2 vblanks
+		;             | vblank     | iteration  |  Y    X  |  Y    X
+		;-------------+------------+------------+----------+----------
+		; NTSC FC/NES | 29780      | 12.005     | $09  $B1 | $13  $62
+		; PAL NES     | 33247      | 12.005     | $0A  $D2 | $15  $A4
+		; Dendy       | 35464      | 12.005     | $0B  $8A | $17  $14
+
+		; check if we encountered 2 vblanks...
+		tya
+		cmp #$10
+		bcc nodiv2
+		lsr a ; if so, divide by 2.
+nodiv2:
+		sec
+		sbc #9
+		; system      | A
+		;-------------+--
+		; NTSC FC/NES | 0
+		; PAL NES     | 1
+		; Dendy       | 2
+		; unknown     | 3+
+		beq +
+		lda #larchf_pal
+	+	ora #larch_nintendo
+		ora lk_archtype
+		sta lk_archtype