--- a/ym2612.c	Thu Mar 26 23:53:35 2020 -0700
+++ b/ym2612.c	Fri Mar 27 00:03:58 2020 -0700
@@ -779,6 +779,19 @@
 	return inc;
 }
 
+void ym_vgm_log(ym2612_context *context, uint32_t master_clock, vgm_writer *vgm)
+{
+	vgm_ym2612_init(vgm, 6 * master_clock / context->clock_inc);
+	context->vgm = vgm;
+	for (uint8_t reg = YM_PART1_START; reg < YM_REG_END; reg++) {
+		vgm_ym2612_part1_write(context->vgm, context->current_cycle, reg, context->part1_regs[reg - YM_PART1_START]);
+	}
+	
+	for (uint8_t reg = YM_PART2_START; reg < YM_REG_END; reg++) {
+		vgm_ym2612_part2_write(context->vgm, context->current_cycle, reg, context->part2_regs[reg - YM_PART2_START]);
+	}
+}
+
 void ym_data_write(ym2612_context * context, uint8_t value)
 {
 	context->write_cycle = context->current_cycle;
@@ -791,11 +804,17 @@
 		if (context->selected_reg < YM_PART2_START) {
 			return;
 		}
+		if (context->vgm) {
+			vgm_ym2612_part2_write(context->vgm, context->current_cycle, context->selected_reg, value);
+		}
 		context->part2_regs[context->selected_reg - YM_PART2_START] = value;
 	} else {
 		if (context->selected_reg < YM_PART1_START) {
 			return;
 		}
+		if (context->vgm) {
+			vgm_ym2612_part1_write(context->vgm, context->current_cycle, context->selected_reg, value);
+		}
 		context->part1_regs[context->selected_reg - YM_PART1_START] = value;
 	}
 	dfprintf(debug_file, "write of %X to reg %X in part %d\n", value, context->selected_reg, context->selected_part+1);