Implement writes from Z80 to YM-2612

3 files changed, 49 insertions, 4 deletions

diff --git a/blastem.c b/blastem.c
index b9a1b6a..f1fc062 100644
--- a/blastem.c
+++ b/blastem.c
@@ -701,6 +701,27 @@ m68k_context * io_read_w(uint32_t location, m68k_context * context)
 	return context;
 }
 
+z80_context * z80_write_ym(uint16_t location, z80_context * context, uint8_t value)
+{
+	genesis_context * gen = context->system;
+	ym_run(gen->ym, (context->current_cycle * MCLKS_PER_Z80) / MCLKS_PER_68K);
+	if (location & 1) {
+		ym_data_write(gen->ym, value);
+	} else if (location & 2) {
+		ym_address_write_part2(gen->ym, value);
+	} else {
+		ym_address_write_part1(gen->ym, value);
+	}
+	return context;
+}
+
+uint8_t z80_read_ym(uint16_t location, z80_context * context)
+{
+	genesis_context * gen = context->system;
+	ym_run(gen->ym, (context->current_cycle * MCLKS_PER_Z80) / MCLKS_PER_68K);
+	return ym_read_status(gen->ym);
+}
+
 typedef struct bp_def {
 	struct bp_def * next;
 	uint32_t address;
@@ -1015,13 +1036,15 @@ int main(int argc, char ** argv)
 	x86_z80_options z_opts;
 	init_x86_z80_opts(&z_opts);
 	init_z80_context(&z_context, &z_opts);
-	z_context.next_context = &v_context;
+
+	genesis_context gen;	
+
+	z_context.system = &gen;
 	z_context.mem_pointers[0] = z80_ram;
 	z_context.sync_cycle = z_context.target_cycle = MCLKS_PER_FRAME/MCLKS_PER_Z80;
 	z_context.int_cycle = CYCLE_NEVER;
 	z_context.mem_pointers[1] = z_context.mem_pointers[2] = (uint8_t *)cart;
 	
-	genesis_context gen;
 	gen.z80 = &z_context;
 	gen.vdp = &v_context;
 	gen.ym = &y_context;
diff --git a/z80_to_x86.h b/z80_to_x86.h
index f5e5a39..93af9cc 100644
--- a/z80_to_x86.h
+++ b/z80_to_x86.h
@@ -47,7 +47,7 @@ typedef struct {
 	native_map_slot * static_code_map;
 	native_map_slot * banked_code_map;
 	void *            options;
-	void *            next_context;
+	void *            system;
 	uint8_t           ram_code_flags[(8 * 1024)/128/8];
 } z80_context;
 
diff --git a/zruntime.S b/zruntime.S
index c2ffe19..b0c492b 100644
--- a/zruntime.S
+++ b/zruntime.S
@@ -90,6 +90,8 @@ z80_read_byte_noinc:
 	jb z80_read_ram
 	cmp $0x8000, %r13w
 	jae z80_read_bank
+	cmp $0x6000, %r13w
+	jb z80_read_ym2612
 	/* TODO: Bank reg, YM-2612, PSG/VDP */
 	mov $0xFF, %r13b
 	ret
@@ -108,6 +110,15 @@ z80_read_bank:
 slow_bank_read:
 	/* TODO: Call into C to implement this */
 	ret
+z80_read_ym2612:
+	call z80_save_context
+	mov %r13w, %di
+	push %rsi
+	call z80_read_ym
+	pop %rsi
+	mov %al, %r13b
+	call z80_load_context
+	ret
 
 	.global z80_write_byte
 z80_write_byte:
@@ -118,7 +129,9 @@ z80_write_byte_noinc:
 	cmp $0x8000, %r14w
 	jae z80_write_bank
 	cmp $0x6000, %r14w
-	je z80_write_bank_reg
+	jb z80_write_ym2612
+	cmp $0x6100, %r14w
+	jb z80_write_bank_reg
 	/* TODO: YM-2612, PSG/VDP */
 	ret
 z80_write_ram:
@@ -146,6 +159,15 @@ z80_write_bank:
 slow_bank_write:
 	/* TODO: Call into C to implement this */
 	ret
+z80_write_ym2612:
+	and $0x3, %r14w
+	call z80_save_context
+	mov %r14w, %di
+	mov %r13b, %dl
+	call z80_write_ym
+	mov %rax, %rsi
+	call z80_load_context
+	ret
 z80_write_bank_reg:
 	and $1, %r13w
 	shr %r15w