NES: fixed clipping, update presets, apu.c/h, vrambuf.c

doc/notes.txt

@@ -95,6 +95,7 @@ TODO:
 - show .map file in listings? memory map view?
 - open ROM from URL?
 - NES: disassembly not aligned on PC
+- NES: vrambuf.c for Solarian
 
 
 WEB WORKER FORMAT

presets/nes/apu.c

@@ -0,0 +1,20 @@
+
+
+#include "apu.h"
+
+#include <string.h>
+
+const unsigned char APUINIT[0x13] = {
+  0x30,0x08,0x00,0x00,
+  0x30,0x08,0x00,0x00,
+  0x80,0x00,0x00,0x00,
+  0x30,0x00,0x00,0x00,
+  0x00,0x00,0x00
+};
+
+void apu_init() {
+  // from https://wiki.nesdev.com/w/index.php/APU_basics
+  memcpy((void*)0x4000, APUINIT, sizeof(APUINIT));
+  APU.fcontrol = 0x40; // frame counter 5-step
+  APU.status = 0x0f; // turn on all channels except DMC
+}

presets/nes/apu.h

@@ -0,0 +1,77 @@
+
+#ifndef _APU_H
+#define _APU_H
+
+#include <nes.h>
+
+// Functions/macros for direct control
+// of APU sound generation
+
+// enable
+#define ENABLE_PULSE0	0x1
+#define ENABLE_PULSE1	0x2
+#define ENABLE_TRIANGLE	0x4
+#define ENABLE_NOISE	0x8
+#define ENABLE_DMC	0x10
+
+#define APU_ENABLE(enable)\
+  APU.status = (enable);
+
+// pulse channels
+#define DUTY_75 0xc0
+#define DUTY_50 0x80
+#define DUTY_25 0x40
+#define DUTY_12 0x00
+
+#define PULSE_ENVLOOP	0x20
+#define PULSE_CONSTVOL	0x10
+#define PULSE_VOLENVMASK 0xf
+
+#define PULSE_CH0	0
+#define PULSE_CH1	1
+
+#define APU_PULSE_DECAY(channel,period,duty,decay,len)\
+  APU.pulse[channel].period_low = (period)&0xff;\
+  APU.pulse[channel].len_period_high = (((period)>>8)&7) | ((len)<<3);\
+  APU.pulse[channel].control = (duty) | (decay);
+
+#define APU_PULSE_SUSTAIN(channel,period,duty,vol)\
+  APU.pulse[channel].period_low = (period)&0xff;\
+  APU.pulse[channel].len_period_high = (((period)>>8)&7);\
+  APU.pulse[channel].control = (duty) | (vol) | (PULSE_CONSTVOL|PULSE_ENVLOOP);
+
+#define APU_PULSE_CONTROL(channel,duty,decay)\
+  APU.pulse[channel].control = (duty) | (decay);
+
+
+// triangle channel
+#define TRIANGLE_LC_HALT	0x80
+#define TRIANGLE_LC_MASK	0x7f
+
+#define APU_TRIANGLE_SUSTAIN(period)\
+  APU.triangle.counter = 0xc0;\
+  APU.triangle.period_low = (period) & 0xff;\
+  APU.triangle.len_period_high = (period) >> 8;
+
+// noise channel
+#define NOISE_ENVLOOP	0x20
+#define NOISE_CONSTVOL	0x10
+#define NOISE_VOLENVMASK 0xf
+
+#define NOISE_PERIOD_BUZZ	0x80
+
+#define APU_NOISE_SUSTAIN(_period,vol)\
+    APU.noise.control = (vol) | (NOISE_ENVLOOP|NOISE_CONSTVOL);\
+    APU.noise.period = (_period);
+
+#define APU_NOISE_DECAY(_period,_decay,_len)\
+    APU.noise.control = (_decay);\
+    APU.noise.period = (_period);\
+    APU.noise.len = (_len);
+
+
+// initialize APU with default state
+void apu_init(void);
+
+
+#endif

presets/nes/bcd.c

@@ -0,0 +1,22 @@
+
+#include "neslib.h"
+
+word bcd_add(word a, word b) {
+  word result = 0;
+  byte c = 0;
+  byte shift = 0;
+  while (shift < 16) {
+    byte d = (a & 0xf) + (b & 0xf) + c;
+    c = 0;
+    while (d >= 10) {
+      c++;
+      d -= 10;
+    }
+    result |= d << shift;
+    shift += 4;
+    a >>= 4;
+    b >>= 4;
+  }
+  return result;
+}
+

presets/nes/bcd.h

@@ -0,0 +1,2 @@
+
+unsigned int bcd_add(unsigned int a, unsigned int b);

presets/nes/climber.c

@@ -8,6 +8,14 @@
 // include CC65 NES Header (PPU)
 #include <nes.h>
 
+// BCD arithmetic support
+#include "bcd.h"
+//#link "bcd.c"
+
+// VRAM update buffer
+#include "vrambuf.h"
+//#link "vrambuf.c"
+
 // link the pattern table into CHR ROM
 //#link "chr_generic.s"
 
@@ -22,12 +30,6 @@ extern char demo_sounds[];
 
 typedef enum { SND_START, SND_HIT, SND_COIN, SND_JUMP } SFXIndex;
 
-// define basic types
-typedef unsigned char byte;
-typedef signed char sbyte;
-typedef unsigned short word;
-typedef enum { false, true } bool;
-
 ///// DEFINES
 
 #define COLS 30		// floor width in tiles
@@ -66,7 +68,7 @@ static byte player_screen_y = 0;
 // score (BCD)
 static byte score = 0;
 
-// flash animation (virtual bright)
+// screen flash animation (virtual bright)
 static byte vbright = 4;
 
 // random byte between (a ... b-1)
@@ -75,15 +77,6 @@ byte rndint(byte a, byte b) {
   return (rand() % (b-a)) + a;
 }
 
-byte bcdadd(byte a, byte b) {
-  byte c = (a & 0xf) + (b & 0xf);
-  if (c < 10) {
-    return a + b;
-  } else {
-    return (c-10) + 0x10 + (a & 0xf0) + (b & 0xf0);
-  }
-}
-
 ///// OAM buffer (for sprites)
 
 #define OAMBUF ((unsigned char*) 0x200)
@@ -102,46 +95,10 @@ word getntaddr(byte x, byte y) {
 
 // convert nametable address to attribute address
 word nt2attraddr(word a) {
-  return (a & 0x2c00) | 0x3c0 | (a & 0x0C00) | 
+  return (a & 0x2c00) | 0x3c0 |
     ((a >> 4) & 0x38) | ((a >> 2) & 0x07);
 }
 
-///// VRAM UPDATE BUFFER
-
-#define VBUFSIZE 64
-byte updbuf[VBUFSIZE];	// update buffer
-byte updptr = 0;	// index to end of buffer
-
-// add EOF marker to buffer
-void cendbuf() {
-  updbuf[updptr] = NT_UPD_EOF;
-}
-
-// flush buffer now, waiting for next frame
-void cflushnow() {
-  // make sure buffer has EOF marker
-  cendbuf();
-  // wait for next frame to flush update buffer
-  // this will also set the scroll registers properly
-  ppu_wait_frame();
-  // clear the buffer
-  updptr = 0;
-  cendbuf();
-}
-
-// add multiple characters to update buffer
-// using horizontal increment
-void putbytes(word addr, char* str, byte len) {
-  if (updptr >= VBUFSIZE-4-len) cflushnow();
-  updbuf[updptr++] = (addr >> 8) | NT_UPD_HORZ;
-  updbuf[updptr++] = addr & 0xff;
-  updbuf[updptr++] = len;
-  while (len--) {
-    	updbuf[updptr++] = *str++;
-  }
-  cendbuf();
-}
-
 /// METASPRITES
 
 // define a 2x2 metasprite
@@ -178,7 +135,13 @@ DEF_METASPRITE_2x2_FLIP(playerLJump, 0xe8, 0);
 DEF_METASPRITE_2x2_FLIP(playerLClimb, 0xec, 0);
 DEF_METASPRITE_2x2_FLIP(playerLSad, 0xf0, 0);
 
-DEF_METASPRITE_2x2(personToSave, 0xba, 1);
+//DEF_METASPRITE_2x2(personToSave, 0xba, 1);
+const unsigned char personToSave[]={
+        0,      0,      (0xba)+0,   3, 
+        0,      8,      (0xba)+2,   0, 
+        8,      0,      (0xba)+1,   3, 
+        8,      8,      (0xba)+3,   0, 
+        128};
 
 const unsigned char* const playerRunSeq[16] = {
   playerLRun1, playerLRun2, playerLRun3, 
@@ -353,6 +316,8 @@ void draw_entire_stage() {
   byte y;
   for (y=0; y<ROWS; y++) {
     draw_floor_line(y);
+    // allow buffer to flush, delaying a frame
+    cflushnow();
   }
 }
 
@@ -649,7 +614,7 @@ void pickup_object(Actor* actor) {
         sfx_play(SND_HIT,0);
         vbright = 8; // flash
       } else {
-        score = bcdadd(score, 1);
+        score = bcd_add(score, 1);
         sfx_play(SND_COIN,0);
       }
     }

presets/nes/ex3.asm

@@ -6,8 +6,11 @@
 	seg.u RAM
 	org $0
 
-ScrollX	byte	; used during NMI
-ScrollY	byte	; used during NMI
+ScrollPos	byte	; used during NMI
+Rand		byte
+Temp1		byte
+
+SpriteBuf	equ	$200
 
 ;;;;; NES CARTRIDGE HEADER
 
@@ -24,6 +27,7 @@ Start:
 	jsr SetPalette		;set colors
         jsr FillVRAM		;set PPU RAM
         jsr WaitSync		;wait for VSYNC (and PPU warmup)
+        jsr InitSprites
         lda #0
         sta PPU_ADDR
         sta PPU_ADDR		;PPU addr = 0
@@ -51,6 +55,33 @@ FillVRAM: subroutine
 	bne .loop
         rts
 
+;
+InitSprites: subroutine
+	lda #1
+        ldx #0
+.loop
+	sta SpriteBuf,x
+        jsr NextRandom
+        inx
+        bne .loop
+        rts
+
+;
+MoveSprites: subroutine
+	lda #1
+        ldx #0
+.loop
+	sta Temp1
+        and #3
+        clc
+        adc SpriteBuf,x
+	sta SpriteBuf,x
+        lda Temp1
+        jsr NextRandom
+        inx
+        bne .loop
+        rts
+
 ; set palette colors
 
 SetPalette: subroutine
@@ -76,34 +107,21 @@ SetPalette: subroutine
 
 NMIHandler:
 	SAVE_REGS
+; load sprites
+	lda #$02
+        sta PPU_OAM_DMA
 ; update scroll position (must be done after VRAM updates)
-	jsr ReadJoypad
-        pha
-        and #$03
-        tay
-        lda ScrollDirTab,y
-        clc
-        adc ScrollX
-        sta ScrollX
+	inc ScrollPos
+        lda ScrollPos
         sta PPU_SCROLL
-        pla
-        lsr
-        lsr
-        and #$03
-        tay
-        lda ScrollDirTab,y
-        clc
-        adc ScrollY
-        sta ScrollY
+        lda #0
         sta PPU_SCROLL
+; move sprites
+	jsr MoveSprites
 ; reload registers
         RESTORE_REGS
 	rti
 
-; Scroll direction lookup table
-ScrollDirTab:
-	hex 00 01 ff 00
- 
 ;;;;; CONSTANT DATA
 
 	align $100

presets/nes/horizmask.c

@@ -0,0 +1,147 @@
+
+#include "neslib.h"
+#include <string.h>
+
+// 0 = horizontal mirroring
+// 1 = vertical mirroring
+#define NES_MIRRORING 1
+
+// VRAM update buffer
+#include "vrambuf.h"
+//#link "vrambuf.c"
+
+// link the pattern table into CHR ROM
+//#link "chr_generic.s"
+
+// function to write a string into the name table
+//   adr = start address in name table
+//   str = pointer to string
+void put_str(unsigned int adr, const char *str) {
+  vram_adr(adr);        // set PPU read/write address
+  vram_write(str, strlen(str)); // write bytes to PPU
+}
+
+static word x_scroll = 0;
+static byte bldg_height = 8;
+static byte bldg_width = 8;
+static byte bldg_char = 1;
+static byte bldg_attr = 0x55;
+
+#define PLAYROWS 24
+
+word nt2attraddr(word a) {
+  return (a & 0x2c00) | 0x3c0 |
+    ((a >> 4) & 0x38) | ((a >> 2) & 0x07);
+}
+
+void update_nametable() {
+  word addr;
+  char buf[PLAYROWS];
+  // divide x_scroll by 8
+  // to get nametable X position
+  byte x = ((x_scroll >> 3)+32) & 63;
+  if (x < 32)
+    addr = NTADR_A(x, 4);
+  else
+    addr = NTADR_B(x&31, 4);
+  // create vertical slice
+  // clear empty space
+  memset(buf, 0, PLAYROWS-bldg_height);
+  // draw roof
+  buf[PLAYROWS-bldg_height-1] = bldg_char & 3;
+  // draw rest of building
+  memset(buf+PLAYROWS-bldg_height, bldg_char, bldg_height);
+  // draw vertical slice in name table
+  putbytes(addr ^ 0xc000, buf, sizeof(buf));
+  // every 4 columns, update attribute table
+  if ((x & 3) == 1) {
+    // compute attribute table address
+    // of upper attribute block
+    addr = nt2attraddr(addr) + 8*4;
+    VRAMBUF_PUT(addr, bldg_attr, 0);
+    // put lower attribute block
+    addr += 8;
+    VRAMBUF_PUT(addr, bldg_attr, 0);
+    cendbuf();
+  }
+  // generate new building?
+  if (--bldg_width == 0) {
+    bldg_height = (rand8() & 7) + 2;
+    bldg_width = (rand8() & 3) * 4 + 4;
+    bldg_char = (rand8() & 15);
+    bldg_attr = rand8();
+  }
+}
+
+// function to scroll window up and down until end
+void scroll_demo() {
+  // infinite loop
+  while (1) {
+    // update nametable every 8 pixels
+    if ((x_scroll & 7) == 0) {
+      update_nametable();
+    }
+    // manually force vram update
+    ppu_wait_nmi();
+    flush_vram_update(updbuf);
+    cclearbuf();
+    // reset ppu address
+    vram_adr(0x0);
+    // set scroll register
+    // and increment x_scroll
+    split(x_scroll++, 0);
+  }
+}
+
+const char PALETTE[32] = {
+  0x03,			// background color
+
+  0x11,0x30,0x27, 0,	// background 0
+  0x1c,0x20,0x2c, 0,	// background 1
+  0x00,0x10,0x20, 0,	// background 2
+  0x06,0x16,0x26, 0,	// background 3
+
+  0x16,0x35,0x24, 0,	// sprite 0
+  0x00,0x37,0x25, 0,	// sprite 1
+  0x0d,0x2d,0x3a, 0,	// sprite 2
+  0x0d,0x27,0x2a	// sprite 3
+};
+
+// main function, run after console reset
+void main(void) {
+  // set palette colors
+  pal_all(PALETTE);
+
+  // write text to name table
+  put_str(NTADR_A(7,0), "Nametable A, Line 0");
+  put_str(NTADR_A(7,1), "Nametable A, Line 1");
+  put_str(NTADR_A(7,2), "Nametable A, Line 2");
+  vram_adr(NTADR_A(0,3));
+  vram_fill(5, 32);
+  put_str(NTADR_A(2,4), "Nametable A, Line 4");
+  put_str(NTADR_A(2,15),"Nametable A, Line 15");
+  put_str(NTADR_A(2,27),"Nametable A, Line 27");
+  put_str(NTADR_B(2,4), "Nametable B, Line 4");
+  put_str(NTADR_B(2,15),"Nametable B, Line 15");
+  put_str(NTADR_B(2,27),"Nametable B, Line 27");
+  
+  // set attributes
+  vram_adr(0x23c0);
+  vram_fill(0x55, 8);
+  
+  // set sprite 0
+  oam_clear();
+  oam_spr(0, 30, 1, 1, 0);
+  
+  // clip left 8 pixels of screen
+  ppu_mask(MASK_SPR|MASK_BG);
+  
+  // clear vram buffer
+  cclearbuf();
+  
+  // enable PPU rendering (turn on screen)
+  ppu_on_all();
+
+  // scroll window back and forth
+  scroll_demo();
+}

presets/nes/music.c

@@ -4,7 +4,8 @@
 
 #include "neslib.h"
 
-typedef unsigned char byte;
+#include "apu.h"
+//#link "apu.c"
 
 //
 // MUSIC ROUTINES
@@ -41,13 +42,6 @@ byte next_music_byte() {
   return *music_ptr++;
 }
 
-#define DUTY_75 0xc0
-#define DUTY_50 0x80
-#define DUTY_25 0x40
-#define DUTY_12 0x00
-
-#define DUTY (DUTY_25 | 0x1)	// decay rate == 1
-
 void play_music() {
   static byte ch = 0;
   if (music_ptr) {
@@ -56,25 +50,9 @@ void play_music() {
       if ((note & 0x80) == 0) {
         int period = note_table[note & 63];
         if (ch == 0) {
-          APU.pulse[0].period_low = period & 0xff;
-          APU.pulse[0].len_period_high = period >> 8;
-          APU.pulse[0].control = DUTY;
+          APU_PULSE_DECAY(0, period, DUTY_25, 2, 10);
         } else {
-          APU.pulse[1].period_low = period & 0xff;
-          APU.pulse[1].len_period_high = period >> 8;
-          APU.pulse[1].control = DUTY;
-          /*
-          //period = note_table_tri[note & 63];
-          period >>= 1;
-          APU.triangle.counter = 0xc0;
-          APU.triangle.period_low = period & 0xff;
-          APU.triangle.len_period_high = period >> 8;
-          */
-          /*
-          APU.noise.control = 0x4;
-          APU.noise.period = 0xe;
-          APU.noise.len = 0xf;
-          */
+          APU_PULSE_DECAY(1, period, DUTY_25, 2, 10);
         }
         ch = ch^1;
       } else {
@@ -92,24 +70,9 @@ void start_music(const byte* music) {
   cur_duration = 0;
 }
 
-const byte APUINIT[0x13] = {
-  0x30,0x08,0x00,0x00,
-  0x30,0x08,0x00,0x00,
-  0x80,0x00,0x00,0x00,
-  0x30,0x00,0x00,0x00,
-  0x00,0x00,0x00
-};
-
-void init_apu() {
-  // from https://wiki.nesdev.com/w/index.php/APU_basics
-  memcpy((void*)0x4000, APUINIT, sizeof(APUINIT));
-  APU.fcontrol = 0x40; // frame counter 5-step
-  APU.status = 0x0f; // turn on all channels except DMC
-}
-
 void main(void)
 {
-  init_apu();
+  apu_init();
   music_ptr = 0;
   while (1) {
     if (!music_ptr) start_music(music1);

presets/nes/neslib.h

@@ -1,3 +1,5 @@
+#ifndef _NESLIB_H
+#define _NESLIB_H
 /*
  (C) 2015 Alex Semenov (Shiru)
  (C) 2016 Lauri Kasanen
@@ -30,8 +32,14 @@
 //           unrle_vram renamed to vram_unrle, with adr argument removed
 //  060414 - many fixes and improvements, including sequental VRAM updates
 //  previous versions were created since mid-2011, there were many updates
+//  xxxx19 - updated by sehugg@8bitworkshop
 
 
+// define basic types for convenience
+typedef unsigned char byte;	// 8-bit unsigned
+typedef signed char sbyte;	// 8-bit signed
+typedef unsigned short word;	// 16-bit signed
+typedef enum { false, true } bool;	// boolean
 
 
 
@@ -300,3 +308,6 @@ void __fastcall__ nmi_set_callback(void (*callback)(void));
 
 #define MSB(x)			(((x)>>8))
 #define LSB(x)			(((x)&0xff))
+
+#endif /* neslib.h */
+

presets/nes/shoot2.c

@@ -5,17 +5,23 @@
 
 #include "neslib.h"
 
+// APU (sound) support
+#include "apu.h"
+//#link "apu.c"
+
+// BCD arithmetic support
+#include "bcd.h"
+//#link "bcd.c"
+
+// VRAM update buffer
+#include "vrambuf.h"
+//#link "vrambuf.c"
+
 #define COLS 32
 #define ROWS 28
 
 //#define DEBUG_FRAMERATE
 
-typedef unsigned char byte;
-typedef signed char sbyte;
-typedef unsigned short word;
-
-///
-
 const char PALETTE[32] = {
   0x0f,
 
@@ -131,59 +137,11 @@ const char TILESET[128*8*2] = {/*{w:8,h:8,bpp:1,count:128,brev:1,np:2,pofs:8,rem
 #define CHAR(x) ((x)-' ')
 #define BLANK 0
 
-// VRAM UPDATE BUFFER
-
-#define VBUFSIZE 96
-byte updbuf[VBUFSIZE];
-byte updptr = 0;
-
-void cendbuf() {
-  updbuf[updptr] = NT_UPD_EOF;
-}
-
-void cflushnow() {
-  cendbuf();
-  ppu_wait_nmi();
-  flush_vram_update(updbuf);
-  updptr = 0;
-  cendbuf();
-  vram_adr(0x0);
-}
-
-void vdelay(byte count) {
-  while (count--) cflushnow();
-}
-
-void putchar(byte x, byte y, char ch) {
-  word addr = NTADR_A(x,y);
-  if (updptr >= VBUFSIZE-4) cflushnow();
-  updbuf[updptr++] = addr >> 8;
-  updbuf[updptr++] = addr & 0xff;
-  updbuf[updptr++] = ch;
-  cendbuf();
-}
-
-void putbytes(byte x, byte y, char* str, byte len) {
-  word addr = NTADR_A(x,y);
-  if (updptr >= VBUFSIZE-4-len) cflushnow();
-  updbuf[updptr++] = (addr >> 8) | NT_UPD_HORZ;
-  updbuf[updptr++] = addr & 0xff;
-  updbuf[updptr++] = len;
-  while (len--) {
-    	updbuf[updptr++] = *str++;
-  }
-  cendbuf();
-}
-
-void putstring(byte x, byte y, char* str) {
-  putbytes(x, y, str, strlen(str));
-}
-
 void clrscr() {
   updptr = 0;
   cendbuf();
   ppu_off();
-  vram_adr(0x2000);
+  vram_adr(NAMETABLE_A);
   vram_fill(BLANK, 32*28);
   vram_adr(0x0);
   ppu_on_all();
@@ -203,26 +161,7 @@ void draw_bcd_word(byte col, byte row, word bcd) {
     buf[j] = CHAR('0'+(bcd&0xf));
     bcd >>= 4;
   }
-  putbytes(col, row, buf, 5);
-}
-
-word bcd_add(word a, word b) {
-  word result = 0;
-  byte c = 0;
-  byte shift = 0;
-  while (shift < 16) {
-    byte d = (a & 0xf) + (b & 0xf) + c;
-    c = 0;
-    while (d >= 10) {
-      c++;
-      d -= 10;
-    }
-    result |= d << shift;
-    shift += 4;
-    a >>= 4;
-    b >>= 4;
-  }
-  return result;
+  putbytes(NTADR_A(col, row), buf, 5);
 }
 
 // GAME CODE
@@ -261,17 +200,17 @@ typedef struct {
 } AttackingEnemy;
 
 typedef struct {
-  signed char dx;
   byte xpos;
-  signed char dy;
   byte ypos;
+  signed char dx;
+  signed char dy;
 } Missile;
 
 typedef struct {
-  byte name;
-  byte tag;
   byte x;
   byte y;
+  byte name;
+  byte tag;
 } Sprite;
 
 #define ENEMIES_PER_ROW 8
@@ -366,7 +305,7 @@ void draw_row(byte row) {
     }
     x += 3;
   }
-  putbytes(0, y, buf, sizeof(buf));
+  putbytes(NTADR_A(0, y), buf, sizeof(buf));
 }
 
 void draw_next_row() {
@@ -724,37 +663,30 @@ void new_player_ship() {
 
 void set_sounds() {
   byte i;
-  byte enable = 0x1 | 0x2 | 0x8;
+  // these channels decay, so ok to always enable
+  byte enable = ENABLE_PULSE0|ENABLE_PULSE1|ENABLE_NOISE;
   // missile fire sound
   if (missiles[PLYRMISSILE].ypos != YOFFSCREEN) {
-    APU.pulse[0].period_low = missiles[PLYRMISSILE].ypos ^ 0xff;
-    APU.pulse[0].len_period_high = 0;
-    APU.pulse[0].control = 0x80 | 0x30 | 6;
+    APU_PULSE_SUSTAIN(0, missiles[PLYRMISSILE].ypos ^ 0xff, DUTY_50, 6);
   } else {
-    APU.pulse[0].control = 0x30;
+    APU_PULSE_CONTROL(0, DUTY_50, 1);
   }
   // enemy explosion sound
   if (player_exploding && player_exploding < 8) {
-    APU.noise.control = 4;
-    APU.noise.period = 8 + player_exploding;
-    APU.noise.len = 15;
+    APU_NOISE_DECAY(8 + player_exploding, 5, 15);
   } else if (enemy_exploding) {
-    APU.noise.control = 2;
-    APU.noise.period = 8 + enemy_exploding;
-    APU.noise.len = 8;
+    APU_NOISE_DECAY(8 + enemy_exploding, 2, 8);
   }
   // set diving sounds for spaceships
   for (i=0; i<2; i++) {
     register AttackingEnemy* a = i ? &attackers[4] : &attackers[0];
     if (a->findex && !a->returning) {
       byte y = a->y >> 8;
-      APU.triangle.counter = 0xc0;
-      APU.triangle.period_low = y;
-      APU.triangle.len_period_high = 1;
-      enable |= 0x4;
+      APU_TRIANGLE_SUSTAIN(0x100 | y);
+      enable |= ENABLE_TRIANGLE;
     }
   }
-  APU.status = enable;
+  APU_ENABLE(enable);
 }
 
 static char starx[32];
@@ -783,7 +715,7 @@ void play_round() {
   register byte t0;
   byte end_timer = 255;
   add_score(0);
-  putstring(0, 0, "PLAYER 1");
+  //putbytes(NTADR_A(0, 1), "PLAYER 1", 8);
   setup_formation();
   clrobjs();
   formation_direction = 1;
@@ -851,7 +783,7 @@ void set_shifted_pattern(const byte* src, word dest, byte shift) {
   vram_write(buf, sizeof(buf));
 }
 
-void setup_tileset() {
+void setup_graphics() {
   byte i;
   word src;
   word dest;
@@ -869,26 +801,14 @@ void setup_tileset() {
     set_shifted_pattern(&TILESET[src], dest, i);
     dest += 3*16;
   }
-}
-
-const byte APUINIT[0x13] = {
-  0x30,0x08,0x00,0x00,
-  0x30,0x08,0x00,0x00,
-  0x80,0x00,0x00,0x00,
-  0x30,0x00,0x00,0x00,
-  0x00,0x00,0x00
-};
-
-void init_apu() {
-  // from https://wiki.nesdev.com/w/index.php/APU_basics
-  memcpy((void*)0x4000, APUINIT, sizeof(APUINIT));
-  APU.fcontrol = 0x40; // frame counter 5-step
-  APU.status = 0x0f; // turn on all channels except DMC
+  // activate vram buffer
+  cendbuf();
+  set_vram_update(updbuf);
 }
 
 void main() {  
-  setup_tileset();
-  init_apu();
+  setup_graphics();
+  apu_init();
   init_stars();
   player_score = 0;
   while (1) {

presets/nes/siegegame.c

@@ -12,13 +12,7 @@ extern unsigned char palSprites[16];
 extern unsigned char TILESET[8*256];
 
 #define COLS 32
-#define ROWS 28
-
-#define NTADR(x,y) ((0x2000|((y)<<5)|(x)))
-
-typedef unsigned char byte;
-typedef signed char sbyte;
-typedef unsigned short word;
+#define ROWS 27
 
 // read a character from VRAM.
 // this is tricky because we have to wait
@@ -27,10 +21,10 @@ typedef unsigned short word;
 // back to the start of the frame.
 byte getchar(byte x, byte y) {
   // compute VRAM read address
-  word addr = NTADR(x,y);
+  word addr = NTADR_A(x,y);
   byte rd;
   // wait for VBLANK to start
-  waitvsync();
+  ppu_wait_nmi();
   vram_adr(addr);
   vram_read(&rd, 1);
   vram_adr(0x0);
@@ -60,7 +54,7 @@ void vdelay(byte count) {
 }
 
 void cputcxy(byte x, byte y, char ch) {
-  word addr = NTADR(x,y);
+  word addr = NTADR_A(x,y);
   if (updptr >= 60) cflushnow();
   updbuf[updptr++] = addr >> 8;
   updbuf[updptr++] = addr & 0xff;
@@ -69,7 +63,7 @@ void cputcxy(byte x, byte y, char ch) {
 }
 
 void cputsxy(byte x, byte y, char* str) {
-  word addr = NTADR(x,y);
+  word addr = NTADR_A(x,y);
   byte len = strlen(str);
   if (updptr >= 60 - len) cflushnow();
   updbuf[updptr++] = (addr >> 8) | NT_UPD_HORZ;

presets/nes/vrambuf.c

@@ -0,0 +1,40 @@
+
+#include "neslib.h"
+#include "vrambuf.h"
+
+// index to end of buffer
+byte updptr = 0;
+
+// add EOF marker to buffer
+void cendbuf(void) {
+  updbuf[updptr] = NT_UPD_EOF;
+}
+
+void cclearbuf(void) {
+  updptr = 0;
+  cendbuf();
+}
+
+// flush buffer now, waiting for next frame
+void cflushnow(void) {
+  // make sure buffer has EOF marker
+  cendbuf();
+  // wait for next frame to flush update buffer
+  // this will also set the scroll registers properly
+  ppu_wait_frame();
+  // clear the buffer
+  cclearbuf();
+}
+
+// add multiple characters to update buffer
+// using horizontal increment
+void putbytes(word addr, char* str, byte len) {
+  if (updptr >= VBUFSIZE-4-len) cflushnow();
+  updbuf[updptr++] = (addr >> 8) ^ NT_UPD_HORZ;
+  updbuf[updptr++] = addr & 0xff;
+  updbuf[updptr++] = len;
+  while (len--) {
+    	updbuf[updptr++] = *str++;
+  }
+  cendbuf();
+}

presets/nes/vrambuf.h

@@ -0,0 +1,38 @@
+
+#ifndef _VRAMBUF_H
+#define _VRAMBUF_H
+
+#include "neslib.h"
+
+// VBUFSIZE = maximum update buffer bytes
+#define VBUFSIZE 128
+
+// update buffer starts at $100 (stack page)
+#define updbuf ((byte*)0x100)
+
+// index to end of buffer
+extern byte updptr;
+
+// macros
+#define VRAMBUF_PUT(addr,len,flags)\
+  updbuf[updptr++] = ((addr) >> 8) | (flags);\
+  updbuf[updptr++] = (addr) & 0xff;\
+  updbuf[updptr++] = (len);
+
+#define VRAMBUF_ADD(b)\
+  updbuf[updptr++] = (b);
+
+// add EOF marker to buffer
+void cendbuf(void);
+
+// clear update buffer
+void cclearbuf(void);
+
+// flush buffer now, waiting for next frame
+void cflushnow(void);
+
+// add multiple characters to update buffer
+// using horizontal increment
+void putbytes(word addr, char* str, byte len);
+
+#endif // vrambuf.h

src/platform/nes.ts

@@ -17,6 +17,7 @@ const JSNES_PRESETS = [
   {id:'neslib1.c', name:'Text'},
   {id:'scroll.c', name:'Scrolling'},
   {id:'statusbar.c', name:'Status Bar'},
+  {id:'horizmask.c', name:'Horizontal Scrolling'},
   {id:'sprites.c', name:'Sprites'},
   {id:'metasprites.c', name:'Metasprites'},
   {id:'flicker.c', name:'Flickering Sprites'},
@@ -118,6 +119,7 @@ const _JSNESPlatform = function(mainElement) {
       },
       //TODO: onBatteryRamWrite
     });
+    //nes.ppu.clipToTvSize = false;
     nes.stop = function() {
       // TODO: trigger breakpoint
       self.pause();
@@ -300,10 +302,10 @@ const _JSNESPlatform = function(mainElement) {
     var PPUFLAGS = [
       ["f_nmiOnVblank","NMI_ON_VBLANK"],
       ["f_spVisibility","SPRITES"],
-      ["f_spClipping","CLIP_SPRITES"],
+      ["f_spClipping","NO_CLIP_SPRITES"],
       ["f_dispType","MONOCHROME"],
       ["f_bgVisibility","BACKGROUND"],
-      ["f_bgClipping","CLIP_BACKGROUND"],
+      ["f_bgClipping","NO_CLIP_BACKGROUND"],
     ];
     for (var i=0; i<PPUFLAGS.length; i++) {
       var flag = PPUFLAGS[i];

src/ui.ts

@@ -892,7 +892,7 @@ function _recordVideo() {
   };
   f();
  });
- return true;
+ //TODO? return true;
 }
 
 function setFrameRateUI(fps:number) {

src/worker/workermain.ts

@@ -881,13 +881,12 @@ function linkLD65(step:BuildStep) {
   var binpath = "main";
   if (staleFiles(step, [binpath])) {
     var errors = [];
-    var errmsg = '';
     var LD65 = emglobal.ld65({
       instantiateWasm: moduleInstFn('ld65'),
       noInitialRun:true,
       //logReadFiles:true,
       print:print_fn,
-      printErr:function(s) { errmsg += s + '\n'; }
+      printErr:function(s) { errors.push({msg:s,line:0}); }
     });
     var FS = LD65['FS'];
     var cfgfile = '/' + platform + '.cfg';
@@ -905,8 +904,6 @@ function linkLD65(step:BuildStep) {
       '-o', 'main', '-m', 'main.map'].concat(step.args, libargs);
     //console.log(args);
     execMain(step, LD65, args);
-    if (errmsg.length)
-      errors.push({line:0, msg:errmsg});
     if (errors.length)
       return {errors:errors};
     var aout = FS.readFile("main", {encoding:'binary'});