//! Original ARM Mode 2 program. The CPU copies assets through BIOS services //! and writes affine coefficients/reference points during VBlank. //! The bitmap demos reuse this instruction builder with different assets and page control. use crate::graphics_demo::{GraphicsDemo, GraphicsError}; use gba_core::{ input::Buttons, machine::Machine, memory::{MemoryError, ROM_START}, video::Framebuffer, }; /// Debug words: completed updates, signed pan X, signed pan Y. pub const AFFINE_STATE: u32 = 0x0200_0000; pub struct AffineDemo { runner: GraphicsDemo, } impl AffineDemo { pub fn new() -> Result { Ok(Self { runner: GraphicsDemo::with_program(program(2, false))?, }) } pub fn machine(&self) -> &Machine { self.runner.machine() } pub fn frame( &mut self, buttons: Buttons, output: &mut Framebuffer, ) -> Result { self.runner.frame_with_control(buttons, output, 0x402) } } pub(crate) fn bitmap_program(mode: u16) -> Vec { assert!(matches!(mode, 4 | 5)); program(mode, false) } pub(crate) fn raster_program() -> Vec { program(2, true) } fn program(mode: u16, raster: bool) -> Vec { let bitmap = mode != 2; let mut code = vec![ 0xe3a0_9301, // MOV r9,#0x04000000 0xe3a0_0080, // MOV r0,#128 (forced blank) 0xe1c9_00b0, // STRH r0,[r9] 0, // LDR r0,=palette 0xe3a0_1405, // MOV r1,#0x05000000 0xe3a0_2c01, // MOV r2,#256 halfwords 0xef0b_0000, // CpuSet 0, // LDR r0,=VRAM image 0xe3a0_1406, // MOV r1,#0x06000000 if bitmap { 0xe3a0_2a05 } else { 0xe3a0_2901 }, // MOV r2,#20480 or #16384 words 0xef0c_0000, // CpuFastSet 0, // LDR r0,=IRQ callback 0xe3a0_1403, // MOV r1,#0x03000000 0xe281_1c7f, // ADD r1,r1,#0x7f00 0xe581_00fc, // STR r0,[r1,#252] 0xe3a0_0008, // MOV r0,#8 0xe1c9_00b4, // STRH r0,[r9,#4] (VBlank request) 0xe289_1c02, // ADD r1,r9,#0x200 0xe3a0_0001, // MOV r0,#1 0xe1c1_00b0, // STRH r0,[r1] (IE) 0xe289_ac01, // ADD r10,r9,#0x100 0xe28a_a030, // ADD r10,r10,#0x30 (KEYINPUT) 0xe289_6020, // ADD r6,r9,#0x20 (BG2 affine registers) 0xe3a0_b402, // MOV r11,#0x02000000 0xe3a0_4000, // MOV r4,#0 (signed pan X) 0xe3a0_5000, // MOV r5,#0 (signed pan Y) 0xe3a0_7000, // MOV r7,#0 (updates) 0xe3a0_0b01, // MOV r0,#0x400 0xe380_0000 | u32::from(mode), // ORR r0,r0,#mode (BG2 enabled) 0xe1c9_00b0, // STRH r0,[r9] ]; let frame = code.len(); code.extend([ 0xef05_0000, // VBlankIntrWait 0xe1da_30b0, // LDRH r3,[r10] 0xe313_0010, // TST r3,#Right 0x0284_4002, // ADDEQ r4,r4,#2 0xe313_0020, // TST r3,#Left 0x0244_4002, // SUBEQ r4,r4,#2 0xe313_0040, // TST r3,#Up 0x0245_5002, // SUBEQ r5,r5,#2 0xe313_0080, // TST r3,#Down 0x0285_5002, // ADDEQ r5,r5,#2 0xe313_0008, // TST r3,#Start 0x03a0_4000, // MOVEQ r4,#0 0x03a0_5000, // MOVEQ r5,#0 if bitmap { 0xe3a0_0000 } else { 0xe3a0_0a07 }, // MOV r0,#0 or #0x7000 (tile wrap) 0xe313_0001, // TST r3,#A (Z: disable tile wrapping; bitmap page handled below) if raster { 0xe1a0_0000 } else { 0x03c0_0a02 }, // Raster Z bypasses distortion, not wrapping. 0xe1c9_00bc, // STRH r0,[r9,#12] (BG2CNT) 0xe3a0_0c01, // MOV r0,#256 (PA) 0xe3a0_1000, // MOV r1,#0 (PB) 0xe3a0_cc01, // MOV r12,#256 (PD) 0xe313_0c02, // TST r3,#L (Q: 45-degree rotation) 0x03a0_00b5, // MOVEQ r0,#181 0x03a0_10b5, // MOVEQ r1,#181 0x03a0_c0b5, // MOVEQ r12,#181 0xe313_0c01, // TST r3,#R (W: 2x zoom) 0x01a0_00a0, // MOVEQ r0,r0,LSR #1 0x01a0_10a1, // MOVEQ r1,r1,LSR #1 0x01a0_c0ac, // MOVEQ r12,r12,LSR #1 0xe261_2000, // RSB r2,r1,#0 (PC=-PB) 0xe1c6_00b0, // STRH r0,[r6] (PA) 0xe1c6_10b2, // STRH r1,[r6,#2] (PB) 0xe1c6_20b4, // STRH r2,[r6,#4] (PC) 0xe1c6_c0b6, // STRH r12,[r6,#6] (PD) // Reference = (map center + pan)*256 - matrix*(screen center). 0xe3a0_8078, // MOV r8,#120 0xe000_0098, // MUL r0,r8,r0 (120*PA) 0xe3a0_8050, // MOV r8,#80 0xe020_0198, // MLA r0,r8,r1,r0 (+80*PB) 0xe260_0000, // RSB r0,r0,#0 0xe080_0404, // ADD r0,r0,r4,LSL #8 match mode { 4 => 0xe280_0c78, 5 => 0xe280_0a05, _ => 0xe280_0902, }, // ADD map center X * 256 0xe586_0008, // STR r0,[r6,#8] (BG2X) 0xe3a0_8078, // MOV r8,#120 0xe002_0298, // MUL r2,r8,r2 (120*PC) 0xe3a0_8050, // MOV r8,#80 0xe022_2c98, // MLA r2,r8,r12,r2 (+80*PD) 0xe262_2000, // RSB r2,r2,#0 0xe082_2405, // ADD r2,r2,r5,LSL #8 match mode { 4 => 0xe282_2c50, 5 => 0xe282_2901, _ => 0xe282_2902, }, // ADD map center Y * 256 0xe586_200c, // STR r2,[r6,#12] (BG2Y) 0xe287_7001, // ADD r7,r7,#1 ]); if bitmap { code.extend([ 0xe3a0_0b01, // MOV r0,#0x400 0xe380_0000 | u32::from(mode), // ORR r0,r0,#mode 0xe317_0020, // TST r7,#32 (alternate pages every32 updates) 0x1380_0010, // ORRNE r0,r0,#16 0xe313_0001, // TST r3,#A (Z: force page1) 0x0380_0010, // ORREQ r0,r0,#16 0xe1c9_00b0, // STRH r0,[r9] (page switch during VBlank) ]); } let mut raster_dma_load = None; if raster { code.extend([ 0xe3a0_2402, // MOV r2,#0x02000000 0xe282_2a01, // ADD r2,r2,#0x1000 (PB table) 0xe3a0_0000, // MOV r0,#0 (table row) ]); let row = code.len(); code.extend([ 0xe310_0010, // TST r0,#16 0x0281_8c02, // ADDEQ r8,r1,#512 (base PB + two pixels) 0x1241_8c02, // SUBNE r8,r1,#512 (base PB - two pixels) 0xe313_0001, // TST r3,#A (Z: bypass distortion) 0x01a0_8001, // MOVEQ r8,r1 0xe0c2_80b2, // STRH r8,[r2],#2 0xe280_0001, // ADD r0,r0,#1 0xe350_00a0, // CMP r0,#160 ]); let displacement = row as i32 - code.len() as i32 - 2; code.push(0x1a00_0000 | (displacement as u32 & 0x00ff_ffff)); code.extend([ 0xe3a0_0000, // MOV r0,#0 0xe1c9_0bba, // STRH r0,[r9,#0xba] (disable DMA0) 0xe3a0_0402, // MOV r0,#0x02000000 0xe280_0a01, // ADD r0,r0,#0x1000 0xe589_00b0, // STR r0,[r9,#0xb0] (source) 0xe289_0022, // ADD r0,r9,#0x22 (BG2PB) 0xe589_00b4, // STR r0,[r9,#0xb4] (fixed destination) ]); raster_dma_load = Some(code.len()); code.push(0); // LDR r0,=DMA repeat/HBlank configuration code.push(0xe589_00b8); // STR r0,[r9,#0xb8] (arm DMA0) } code.extend([ 0xe58b_7000, // STR r7,[r11] 0xe58b_4004, // STR r4,[r11,#4] 0xe58b_5008, // STR r5,[r11,#8] ]); let offset = frame as i32 - code.len() as i32 - 2; code.push(0xea00_0000 | (offset as u32 & 0xffffff)); let irq = ROM_START + code.len() as u32 * 4; code.extend([ 0xe280_0c02, // ADD r0,r0,#0x200 (BIOS supplies I/O base) 0xe1d0_10b2, // LDRH r1,[r0,#2] 0xe1c0_10b2, // STRH r1,[r0,#2] (ack IF) 0xe3a0_0403, // MOV r0,#0x03000000 0xe280_0c7f, // ADD r0,r0,#0x7f00 0xe1d0_2fb8, // LDRH r2,[r0,#248] 0xe182_2001, // ORR r2,r2,r1 0xe1c0_2fb8, // STRH r2,[r0,#248] (BIOS flags) 0xe12f_ff1e, // BX lr ]); let palette_address = ROM_START + (code.len() + 3 + usize::from(raster)) as u32 * 4; let mut literals = vec![(3, palette_address), (7, palette_address + 512), (11, irq)]; if let Some(index) = raster_dma_load { literals.push((index, 0xa240_0001)); } for (index, value) in literals { let offset = (code.len() - index - 2) * 4; assert!(offset < 4096); code[index] = 0xe59f_0000 | offset as u32; code.push(value); } let mut rom: Vec = code.into_iter().flat_map(u32::to_le_bytes).collect(); if bitmap { rom.extend(crate::bitmap_demo::assets(mode)); return rom; } let mut palette = [0_u16; 256]; palette[..9].copy_from_slice(&[ 0x4000, 0x0260, 0x03a0, 0x7d20, 0x7e80, 0x001f, 0x421f, 0x03ff, 0x7fff, ]); rom.extend(palette.into_iter().flat_map(u16::to_le_bytes)); let mut vram = vec![0_u8; 0x10000]; for t in 0..4 { for y in 0..8 { for x in 0..8 { vram[t * 64 + y * 8 + x] = (t * 2 + 1 + (x / 2 + y / 2) % 2) as u8; } } } for y in 0..32 { for x in 0..32 { vram[0x8000 + y * 32 + x] = ((x / 4 + 2 * (y / 4)) % 4) as u8; } } rom.extend(vram); rom }