mirror of
https://github.com/RetroPortingToolKit/psxrecomp
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Codex
50 lines
1.4 KiB
C
50 lines
1.4 KiB
C
#ifndef PSXRECOMP_PSX_MEMORY_H
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#define PSXRECOMP_PSX_MEMORY_H
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#include <stdint.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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/* One compile-time main-RAM geometry contract for every runtime subsystem.
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* A target selects retail 2 MiB mirroring or unique 8 MiB decoding. */
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#define PSX_MAIN_RAM_RETAIL_BYTES 0x00200000u
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#define PSX_MAIN_RAM_EXPANDED_BYTES 0x00800000u
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#ifndef PSX_MAIN_RAM_BYTES
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#define PSX_MAIN_RAM_BYTES PSX_MAIN_RAM_RETAIL_BYTES
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#endif
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#if PSX_MAIN_RAM_BYTES != PSX_MAIN_RAM_RETAIL_BYTES && \
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PSX_MAIN_RAM_BYTES != PSX_MAIN_RAM_EXPANDED_BYTES
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#error "PSX_MAIN_RAM_BYTES must select 2 MiB or 8 MiB"
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#endif
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#define PSX_MAIN_RAM_MASK (PSX_MAIN_RAM_BYTES - 1u)
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#define PSX_MAIN_RAM_WORD_MASK (PSX_MAIN_RAM_MASK & ~3u)
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/* Strip KUSEG/KSEG0/KSEG1 and canonicalize within the 8 MiB DRAM decode
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* window. Retail targets fold all four aliases; expanded targets preserve all
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* 23 address bits. */
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static inline uint32_t psx_ram_canonical_offset(uint32_t address) {
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return (address & 0x1FFFFFFFu) & PSX_MAIN_RAM_MASK;
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}
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static inline int psx_ram_resolve(uint32_t address, uint32_t width,
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uint32_t *offset) {
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const uint32_t phys = address & 0x1FFFFFFFu;
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uint32_t off;
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if (phys >= PSX_MAIN_RAM_EXPANDED_BYTES || width == 0u) return 0;
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off = phys & PSX_MAIN_RAM_MASK;
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if (width > PSX_MAIN_RAM_BYTES - off) return 0;
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if (offset) *offset = off;
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return 1;
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}
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#ifdef __cplusplus
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}
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#endif
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#endif
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