mirror of
https://github.com/RetroPortingToolKit/psxrecomp
synced 2026-10-26 02:11:36 -04:00
Matthew Stanley
32 lines
1.5 KiB
C
32 lines
1.5 KiB
C
#ifndef PSX_PACKET_ADDRESS_INDEX_H
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#define PSX_PACKET_ADDRESS_INDEX_H
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#include <stdint.h>
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#include <string.h>
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/* Fixed-size lookup scratch for packet guards. Value zero denotes an empty
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* slot; store array index + 1. First insertion wins, matching the old scan.
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* Capacity must be a power of two and at least twice the node count. */
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typedef struct { uint32_t address,value; } PSXPacketAddressIndex;
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static inline uint32_t psx_packet_address_bucket(uint32_t address,uint32_t capacity) {
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return ((address>>2)*2654435761u)&(capacity-1u);
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}
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static inline void psx_packet_address_index_clear(PSXPacketAddressIndex* slots,uint32_t capacity) {
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memset(slots,0,sizeof(*slots)*capacity);
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}
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static inline void psx_packet_address_index_add(PSXPacketAddressIndex* slots,uint32_t capacity,uint32_t address,uint32_t index) {
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uint32_t bucket=psx_packet_address_bucket(address,capacity);
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for(uint32_t n=0;n<capacity;++n,bucket=(bucket+1u)&(capacity-1u)) {
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if(slots[bucket].value && slots[bucket].address==address)return;
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if(!slots[bucket].value){slots[bucket].address=address;slots[bucket].value=index+1u;return;}
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}
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}
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static inline uint32_t psx_packet_address_index_find(const PSXPacketAddressIndex* slots,uint32_t capacity,uint32_t address) {
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uint32_t bucket=psx_packet_address_bucket(address,capacity);
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for(uint32_t n=0;n<capacity;++n,bucket=(bucket+1u)&(capacity-1u)) {
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if(!slots[bucket].value)return UINT32_MAX;
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if(slots[bucket].address==address)return slots[bucket].value-1u;
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}
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return UINT32_MAX;
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}
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#endif
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