mirror of
https://github.com/RetroPortingToolKit/psxrecomp
synced 2026-10-28 19:07:47 -04:00
Matthew Stanley
66 lines
2.4 KiB
C
66 lines
2.4 KiB
C
/* mod_immediate.h - [[mod_immediate.sites]]: instruction immediates a trusted
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* mod selects at run time.
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*
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* A title lists guarded I-type instructions in game.toml:
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*
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* [mod_immediate]
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* sites = [
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* { address = "0x80023500", expected = "0x28820020", group = 1, values = [64, 128] },
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* ]
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*
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* Selector 0 (the default, restored at every session start) runs the original
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* instruction. Selector N runs the same instruction with values[N-1] as its
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* 16-bit immediate. A mod picks the selector of each group at activation with
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* psx_mod_set_immediate_selector (mod_plugins.h).
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*
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* The instruction bytes in RAM never change, so static AOT code, cached overlays
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* and the interpreter keep matching their original-bytes guards: generated code
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* switches on psx_mod_immediate_select(group) per listed instruction, and the
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* dirty-RAM interpreter substitutes the word with psx_mod_immediate_patch.
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* docs/config_schema.md "Mod immediates" has the config rules.
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*/
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#ifndef PSX_MOD_IMMEDIATE_H
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#define PSX_MOD_IMMEDIATE_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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#define PSX_MOD_IMMEDIATE_GROUPS 64
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#define PSX_MOD_IMMEDIATE_VALUES_MAX 15
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#define PSX_MOD_IMMEDIATE_SITES_MAX 4096
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typedef struct PSXModImmediateSite {
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uint32_t address; /* any segment; stored physical */
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uint32_t expected; /* the complete original instruction word */
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uint32_t group; /* 0..63 */
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uint32_t count; /* 1..PSX_MOD_IMMEDIATE_VALUES_MAX */
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uint16_t values[PSX_MOD_IMMEDIATE_VALUES_MAX]; /* imm16 for selector 1..count */
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} PSXModImmediateSite;
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/* Nonzero while a site exists and any selector is nonzero: the interpreter's
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* per-instruction gate. */
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extern int g_psx_mod_immediate_live;
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/* The title's sites (game config). Copied, sorted by (address, word) and capped
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* at PSX_MOD_IMMEDIATE_SITES_MAX. Returns the number kept. */
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int psx_mod_immediate_set_sites(const PSXModImmediateSite *sites, int count);
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int psx_mod_immediate_site_count(void);
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/* Selector of `group`; 0 for an out-of-range group. Called by generated code. */
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uint32_t psx_mod_immediate_select(uint32_t group);
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/* Session reset: every selector back to 0 (stock instructions). */
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void psx_mod_immediate_reset(void);
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/* The instruction the interpreter executes at `pc`: `insn` itself unless a
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* listed site with that exact word has a nonzero selector. */
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uint32_t psx_mod_immediate_patch(uint32_t pc, uint32_t insn);
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#ifdef __cplusplus
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}
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#endif
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#endif
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