+ //////////////////////////////////////////////////////
+ // special irq handling in the decode buffers (0x0000-0x1000)
+ // we know:
+ // the decode buffers are located in spu memory in the following way:
+ // 0x0000-0x03ff CD audio left
+ // 0x0400-0x07ff CD audio right
+ // 0x0800-0x0bff Voice 1
+ // 0x0c00-0x0fff Voice 3
+ // and decoded data is 16 bit for one sample
+ // we assume:
+ // even if voices 1/3 are off or no cd audio is playing, the internal
+ // play positions will move on and wrap after 0x400 bytes.
+ // Therefore: we just need a pointer from spumem+0 to spumem+3ff, and
+ // increase this pointer on each sample by 2 bytes. If this pointer
+ // (or 0x400 offsets of this pointer) hits the spuirq address, we generate
+ // an IRQ.
+
+ if (unlikely((spu.spuCtrl & CTRL_IRQ)
+ && spu.pSpuIrq < spu.spuMemC+0x1000))
+ {
+ int irq_pos = (spu.pSpuIrq - spu.spuMemC) / 2 & 0x1ff;
+ int left = (irq_pos - spu.decode_pos) & 0x1ff;
+ if (0 < left && left <= ns_to)
+ {
+ //xprintf("decoder irq %x\n", spu.decode_pos);
+ do_irq();
+ }
+ }
+
+ InitREVERB(ns_to);