Add optional Low Input Latency with guarded regional readers

docs/regional/low-input-latency.md

@@ -0,0 +1,43 @@
+# Low Input Latency
+
+Optional, default-off fresher resolved digital P1 input. The original pad reader,
+button-edge logic, dialogue locks, actions and rumble remain in control; no extra
+simulation or rendering is introduced. US/Japan retain 60 Hz and Europe 50 Hz.
+
+Verified original-byte profiles cover USA, all five EU1 languages, both EU2
+revisions and their five languages, and Japan. European routines differ only in
+verified data relocations. Japan retains its original packed P1/P2 BIOS producer;
+the checked cached-P1 store is observed in both original loop callers. Its
+legacy ReadPad button bytes are converted to the canonical host layout before
+priming and back to the original layout before the guest store. P2 stays original.
+
+Requires the companion psxrecomp digital-pad snapshot API. Rebuild the runtime
+and overlays with the added mod_instruction_sites. Never rename old native DLLs
+into a new configuration namespace. Whole-function contracts and device checks
+fall back to original input when a profile or controller mode is unsupported.
+
+Short controller-only LOAD checks pass for USA and English EU2 original revision:
+walking, direction changes, jump/landing, and observed input edges. English EU1
+also has an owner-confirmed responsiveness improvement. The other European
+languages and EU2 Rev 1 have original-byte contract coverage, not new gameplay
+acceptance. Japan's original menu lists the save, but loading into controllable
+gameplay remains unconfirmed after the bounded follow-up, including the byte-
+layout correction. These checks are not campaign certification.
+
+Coverage is offline single-player digital P1. Analog/Hybrid, registered controller
+transforms or sources, configured multiple pads, multitap, netplay, replay and
+input guards retain original input. Unknown guest-only multiplayer patches are
+not validated by this API.
+Short observed taps are latched; discontinuities re-prime without replaying old
+edges. No host API can recover input that the operating system never delivered.
+
+The engine regression is digital_pad_snapshot_test. The optional title fixture
+eu/tests/test_low_input_latency.c accepts owner-extracted regional executables
+and checks original-byte contracts, preserved registers and fallback paths.
+Retail bytes are never distributed. Internal timings are not controller-to-TV
+measurements. Frame interpolation is independent and is not part of this change.
+
+The validated US/EU production paths are unchanged; Japan only received the
+necessary legacy-button byte-layout correction. Re-polling SDL inside the guest hook
+or changing presentation timing needs separate correctness work; neither is an
+additional proven safe latency reduction in this change.

eu/CMakeLists.txt

@@ -96,6 +96,7 @@ if(TOMBI_PC_FEATURES)
     endif()
     # Address-free host policy; guest widescreen hooks use checked EU adapters.
     target_sources(${tombi_target} PRIVATE
+        "${TOMBA_ROOT}/src/mods/tomba_low_input_latency_plugin.c"
         "${TOMBA_ROOT}/src/mods/tomba_hybrid_controller_plugin.c"
         "${TOMBA_ROOT}/src/mods/tomba_skip_fmv_plugin.c")
     if(TARGET ${tombi_target}-pgxp)
@@ -105,6 +106,25 @@ if(TOMBI_PC_FEATURES)
     endif()
     include(CTest)
     if(BUILD_TESTING)
+        add_executable(tombi-low-input-tests tests/test_low_input_latency.c)
+        target_include_directories(tombi-low-input-tests PRIVATE
+            "${PSXRECOMP_ROOT}/runtime/include")
+        target_compile_options(tombi-low-input-tests PRIVATE
+            $<$<C_COMPILER_ID:MSVC>:/UNDEBUG>
+            $<$<NOT:$<C_COMPILER_ID:MSVC>>:-UNDEBUG>)
+        set(TOMBI_INPUT_TEST_MAIN_DIR "" CACHE PATH
+            "Optional owner-extracted EU1 MAIN0..4 directory")
+        if(TOMBI_INPUT_TEST_MAIN_DIR)
+            add_test(NAME tombi_low_input COMMAND tombi-low-input-tests
+                "${TOMBI_INPUT_TEST_MAIN_DIR}/MAIN0.EXE"
+                "${TOMBI_INPUT_TEST_MAIN_DIR}/MAIN1.EXE"
+                "${TOMBI_INPUT_TEST_MAIN_DIR}/MAIN2.EXE"
+                "${TOMBI_INPUT_TEST_MAIN_DIR}/MAIN3.EXE"
+                "${TOMBI_INPUT_TEST_MAIN_DIR}/MAIN4.EXE")
+        else()
+            add_test(NAME tombi_low_input COMMAND tombi-low-input-tests)
+        endif()
+        set_tests_properties(tombi_low_input PROPERTIES SKIP_RETURN_CODE 77)
         add_executable(tombi-widescreen-identity-tests tests/test_widescreen_identity.c
             "${tombi_ws}/eu_widescreen.c")
         target_include_directories(tombi-widescreen-identity-tests PRIVATE

eu/low_input_latency.c

@@ -0,0 +1,2 @@
+/* Regional input implementation is shared; original readers still execute. */
+#include "../src/mods/tomba_low_input_latency_plugin.c"

eu/mods/preloaded/packages/tombi.enhancement.low-input-latency/0.1.0/manifest.toml

@@ -0,0 +1,22 @@
+format_version = 5
+id = "tombi.enhancement.low-input-latency"
+version = "0.1.0"
+name = "Low Input Latency"
+author = "TombiRecomp contributors"
+description = "Uses fresher digital input without changing the original simulation rate."
+resolver = "declarative"
+save_compatibility = "shared"
+
+[[target]]
+game_id = "SCES-01330"
+
+[[feature]]
+id = "low-input-latency"
+name = "Low Input Latency"
+description = "Reduces the original digital controller packet delay. Currently verified for English EU1 Rev 1, offline single-player D-pad. Other languages and controller modes retain original input. Applies at the next game start."
+group = "Gameplay"
+default_enabled = false
+
+[[plugin]]
+feature = "low-input-latency"
+id = "tombi.low-input-latency"

eu/mods/preloaded/packages/tombi.enhancement.low-input-latency/0.1.1/manifest.toml

@@ -0,0 +1,30 @@
+format_version = 5
+id = "tombi.enhancement.low-input-latency"
+version = "0.1.1"
+name = "Low Input Latency"
+author = "TombiRecomp contributors"
+description = "Uses fresher digital input without changing the original simulation rate."
+resolver = "declarative"
+save_compatibility = "shared"
+
+[[target]]
+game_id = "SCUS-94236"
+
+[[target]]
+game_id = "SCES-01330"
+
+[[target]]
+game_id = "SCES-01331"
+
+[[target]]
+game_id = "SLPS-01144"
+
+[[feature]]
+id = "low-input-latency"
+name = "Low Input Latency"
+description = "Reduces digital input packet delay. Verified bindings for USA, both European language sets and Japan. Offline single-player D-pad; other controller modes keep original input. Applies at the next game start."
+group = "Gameplay"
+default_enabled = false
+[[plugin]]
+feature = "low-input-latency"
+id = "tombi.low-input-latency"

eu/pc.toml

@@ -20,6 +20,7 @@ known_md5 = ["5029ec8fee56ec6bb6316bd16ee77d54"]
 known_sha1 = ["2505d958b4439d04844cadd3f968fc7432a48e00"]
 
 [recompiler]
+mod_instruction_sites = ["0x800263B4"]
 bios_config = "../psxrecomp/bios/SCPH1001.toml" # ABI/address metadata only; runtime uses bundled OpenBIOS.
 seeds = "seeds/boot.txt"
 out_dir = "../build-eu-prototype/generated"

eu/release/game.toml

@@ -16,6 +16,7 @@ known_md5 = ["5029ec8fee56ec6bb6316bd16ee77d54"]
 known_sha1 = ["2505d958b4439d04844cadd3f968fc7432a48e00"]
 
 [recompiler]
+mod_instruction_sites = ["0x800263B4"]
 seeds = "seeds/boot.txt"
 out_dir = "cache/generated"
 strict = true

eu/seamless/game.toml

@@ -20,6 +20,7 @@ known_md5 = ["5029ec8fee56ec6bb6316bd16ee77d54"]
 known_sha1 = ["2505d958b4439d04844cadd3f968fc7432a48e00"]
 
 [recompiler]
+mod_instruction_sites = ["0x800263B4"]
 bios_config = "../../psxrecomp/bios/SCPH1001.toml" # ABI/address metadata only; runtime uses bundled OpenBIOS.
 seeds = "../seeds/boot.txt"
 out_dir = "../../build-eu-seamless/generated/boot"

eu/tests/test_low_input_latency.c

@@ -0,0 +1,79 @@
+/* Optional original-disc contract test: pass owner-extracted executables.
+ * No retail bytes, cards, rendering or network are needed in this fixture. */
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "../low_input_latency.c"
+static unsigned char image[0x200000];
+static uint32_t sample,last_legacy;
+static int allowed,reads;
+uint8_t psx_mod_read_byte(uint32_t pc) {return (pc&0x1fffffffu)<sizeof image?image[pc&0x1fffffffu]:0;}
+uint16_t psx_mod_read_half(uint32_t pc) {return psx_mod_read_byte(pc)|(uint16_t)psx_mod_read_byte(pc+1)<<8;}
+uint32_t psx_mod_read_word(uint32_t pc) {return psx_mod_read_half(pc)|(uint32_t)psx_mod_read_half(pc+2)<<16;}
+static void put(uint32_t a,uint32_t v) {for(int i=0;i<4;++i)image[(a&0x1fffffu)+i]=(uint8_t)(v>>(8*i));}
+int psx_mod_read_digital_pad(uint32_t player,PSXModDigitalPadReader *r,uint32_t old,uint32_t *out) {
+    (void)r;last_legacy=old;assert(player==0);++reads;*out=sample;return allowed;
+}
+int psx_mod_register_session_reset_plugin(const char *id,PSXModActivationCallback cb) {(void)id;(void)cb;return 1;}
+int psx_mod_register_activation_plugin(const char *id,PSXModActivationCallback cb) {(void)id;(void)cb;return 1;}
+int psx_mod_register_savestate_plugin(const char *id,PSXModVBlankCallback cb) {(void)id;(void)cb;return 1;}
+int psx_mod_register_instruction_plugin(const char *id,uint32_t pc,uint32_t word,PSXModFunctionEntryCallback cb) {
+    (void)id;(void)cb;
+    for(unsigned i=0;i<sizeof input_profiles/sizeof *input_profiles;++i)
+        if(input_profiles[i].hook==pc && input_profiles[i].instruction==word)return 1;
+    assert(0);return 0;
+}
+int main(int argc,char **argv) {
+    if(argc<2)return 77;
+    for(int input=1;input<argc;++input) {
+        FILE *f=fopen(argv[input],"rb");assert(f);assert(!fseek(f,2048,SEEK_SET));
+        memset(image,0,sizeof image);assert(fread(image+0x10000,1,sizeof image-0x10000,f)>0x20000);fclose(f);
+        const TombaInputProfile *p=0;
+        for(unsigned i=0;i<sizeof input_profiles/sizeof *input_profiles;++i) {
+            const TombaInputProfile *q=&input_profiles[i];
+            if(body_hash(q->start,q->size)==q->hash && body_hash(q->extra,q->extra_size)==q->extra_hash) {p=q;break;}
+        }
+        assert(p);assert(psx_mod_read_word(p->hook)==p->instruction);
+        if(p->kind)put(p->field1,1);
+        else {image[p->field0&0x1fffffu]=0;put(p->field1,4);}
+        CPUState before;memset(&before,0x5a,sizeof before);before.gpr[31]=p->caller;
+        if(p->kind)before.gpr[4]=p->field0;
+        allowed=1;reads=0;
+        for(unsigned bit=0;bit<18;++bit) {
+            sample=bit<16?1u<<bit:bit==16?0:65535;
+            CPUState cpu=before,expected=before;
+            expected.gpr[2]=p->kind?((sample>>8)&0xffu)|((sample&0xffu)<<8):(uint32_t)(int32_t)(int16_t)(uint16_t)sample;
+            read_return(&cpu,p->hook);assert(!memcmp(&cpu,&expected,sizeof cpu));
+        }
+        assert(reads==18);
+        /* Both verified Japanese callers reach the same original P1 store.
+         * Exercise each, not just the first matching regional profile. */
+        if(p->kind) {
+            for(unsigned i=0;i<sizeof input_profiles/sizeof *input_profiles;++i) {
+                const TombaInputProfile *q=&input_profiles[i];
+                if(q->kind!=p->kind || q->hash!=p->hash || q->start!=p->start)continue;
+                CPUState call=before,expected=before;
+                call.gpr[31]=expected.gpr[31]=q->caller;
+                sample=0xa55au;expected.gpr[2]=0x5aa5u;
+                int count=reads;read_return(&call,q->hook);
+                assert(reads==count+1 && !memcmp(&call,&expected,sizeof call));
+            }
+        }
+        /* Priming/fallback receives canonical buttons while preserving the
+         * original guest result when the host reader declines. */
+        CPUState raw=before;raw.gpr[2]=0x1234u;CPUState original=raw;
+        allowed=0;read_return(&raw,p->hook);
+        assert(last_legacy==(p->kind?0x3412u:0x1234u));
+        assert(!memcmp(&raw,&original,sizeof raw));
+        CPUState cpu=before;allowed=0;read_return(&cpu,p->hook);assert(!memcmp(&cpu,&before,sizeof cpu));
+        allowed=1;cpu=before;cpu.gpr[31]=0;CPUState bad=cpu;reads=0;
+        read_return(&cpu,p->hook);assert(!reads && !memcmp(&cpu,&bad,sizeof cpu));
+        if(p->kind)put(p->field1,0);else put(p->field1,7);
+        cpu=before;reads=0;read_return(&cpu,p->hook);assert(!reads && !memcmp(&cpu,&before,sizeof cpu));
+        if(p->kind)put(p->field1,1);else put(p->field1,4);
+        image[p->start&0x1fffffu]^=1;cpu=before;reads=0;
+        read_return(&cpu,p->hook);assert(!reads && !memcmp(&cpu,&before,sizeof cpu));
+        printf("PASS original input ABI: %s\n",argv[input]);
+    }
+}

eu2/CMakeLists.txt

@@ -12,7 +12,10 @@ option(TOMBI_EU2_GEOMETRY_VALIDATE "Private original-vs-HLE differential checks"
 if(TOMBI_EU2_PLAYER_RELEASE AND PSX_DEBUG_TOOLS)
     message(FATAL_ERROR "Player releases must use PSX_DEBUG_TOOLS=OFF")
 endif()
-set(eu2_mods NONE)
+set(input_mods "${CMAKE_CURRENT_BINARY_DIR}/input-preloaded")
+file(COPY "${TOMBA_ROOT}/mods/preloaded/packages/tombi.enhancement.low-input-latency"
+    DESTINATION "${input_mods}/packages")
+set(eu2_mods "${input_mods}")
 if(TOMBI_EU2_SEAMLESS)
     find_package(Python3 REQUIRED COMPONENTS Interpreter)
     execute_process(COMMAND "${Python3_EXECUTABLE}" -I -B
@@ -112,3 +115,5 @@ if(TOMBI_EU2_SEAMLESS)
     endif()
     endif()
 endif()
+
+target_sources(tombi-eu2 PRIVATE "${TOMBA_ROOT}/src/mods/tomba_low_input_latency_plugin.c")

eu2/game.toml

@@ -20,6 +20,7 @@ known_md5 = ["5cbbd8800409d992ce4b6d0df4bd7fab"]
 known_sha1 = ["684dbf0ad03f872511046d40d3cc85b17d839dbf"]
 
 [recompiler]
+mod_instruction_sites = ["0x80026368"]
 bios_config = "../psxrecomp/bios/SCPH1001.toml"
 seeds = "seeds/boot.txt"
 out_dir = "../build-eu2/generated"

eu2/mods/packages/tombi.enhancement.low-input-latency/0.1.1/manifest.toml

@@ -0,0 +1,30 @@
+format_version = 5
+id = "tombi.enhancement.low-input-latency"
+version = "0.1.1"
+name = "Low Input Latency"
+author = "TombiRecomp contributors"
+description = "Uses fresher digital input without changing the original simulation rate."
+resolver = "declarative"
+save_compatibility = "shared"
+
+[[target]]
+game_id = "SCUS-94236"
+
+[[target]]
+game_id = "SCES-01330"
+
+[[target]]
+game_id = "SCES-01331"
+
+[[target]]
+game_id = "SLPS-01144"
+
+[[feature]]
+id = "low-input-latency"
+name = "Low Input Latency"
+description = "Reduces digital input packet delay. Verified bindings for USA, both European language sets and Japan. Offline single-player D-pad; other controller modes keep original input. Applies at the next game start."
+group = "Gameplay"
+default_enabled = false
+[[plugin]]
+feature = "low-input-latency"
+id = "tombi.low-input-latency"

eu2/pc.toml

@@ -20,6 +20,7 @@ known_md5 = ["5cbbd8800409d992ce4b6d0df4bd7fab"]
 known_sha1 = ["684dbf0ad03f872511046d40d3cc85b17d839dbf"]
 
 [recompiler]
+mod_instruction_sites = ["0x80026368"]
 bios_config = "../psxrecomp/bios/SCPH1001.toml"
 seeds = "seeds/boot.txt"
 out_dir = "../build-eu2-seamless/generated/boot"

eu2/release/game.toml

@@ -16,6 +16,7 @@ known_md5 = ["5cbbd8800409d992ce4b6d0df4bd7fab"]
 known_sha1 = ["684dbf0ad03f872511046d40d3cc85b17d839dbf"]
 
 [recompiler]
+mod_instruction_sites = ["0x80026368"]
 seeds = "seeds/boot.txt"
 out_dir = "cache/generated"
 strict = true

eu2/rev1/game.toml

@@ -20,6 +20,7 @@ known_md5 = ["2456298c5fc4c7686e739f02ee165363"]
 known_sha1 = ["ec50074b6fd98f611bae11e3de68d6e76ffdd6d4"]
 
 [recompiler]
+mod_instruction_sites = ["0x800263B4"]
 bios_config = "../psxrecomp/bios/SCPH1001.toml"
 seeds = "seeds/boot.txt"
 out_dir = "../build-eu2/generated"

eu2/rev1/pc.toml

@@ -20,6 +20,7 @@ known_md5 = ["2456298c5fc4c7686e739f02ee165363"]
 known_sha1 = ["ec50074b6fd98f611bae11e3de68d6e76ffdd6d4"]
 
 [recompiler]
+mod_instruction_sites = ["0x800263B4"]
 bios_config = "../psxrecomp/bios/SCPH1001.toml"
 seeds = "seeds/boot.txt"
 out_dir = "../build-eu2-seamless/generated/boot"

eu2/rev1/release/game.toml

@@ -16,6 +16,7 @@ known_md5 = ["2456298c5fc4c7686e739f02ee165363"]
 known_sha1 = ["ec50074b6fd98f611bae11e3de68d6e76ffdd6d4"]
 
 [recompiler]
+mod_instruction_sites = ["0x800263B4"]
 seeds = "seeds/boot.txt"
 out_dir = "cache/generated"
 strict = true

eu2/seamless.toml

@@ -20,6 +20,7 @@ known_md5 = ["5cbbd8800409d992ce4b6d0df4bd7fab"]
 known_sha1 = ["684dbf0ad03f872511046d40d3cc85b17d839dbf"]
 
 [recompiler]
+mod_instruction_sites = ["0x80026368"]
 bios_config = "../psxrecomp/bios/SCPH1001.toml"
 seeds = "seeds/boot.txt"
 out_dir = "../build-eu2-seamless/generated/boot"

game.toml

@@ -27,6 +27,7 @@ known_sha1 = [
 ]
 
 [recompiler]
+mod_instruction_sites = ["0x80028EEC"]
 seeds = "seeds/ghidra_funcs.txt"
 out_dir = "generated"
 strict = true

jp/CMakeLists.txt

@@ -11,7 +11,10 @@ include("${PSXRECOMP_ROOT}/runtime/runtime.cmake")
 # adapter, jp/widescreen_profile.py).
 option(TOMBA_JP_ENHANCEMENTS "Seamless Loading, FMV Skip and Widescreen" OFF)
 set(TOMBA_JP_GENERATED_DIR "${TOMBA_ROOT}/build-jp/generated" CACHE PATH "Japanese boot code directory")
-set(jp_mods NONE)
+set(input_mods "${CMAKE_CURRENT_BINARY_DIR}/input-preloaded")
+file(COPY "${TOMBA_ROOT}/mods/preloaded/packages/tombi.enhancement.low-input-latency"
+    DESTINATION "${input_mods}/packages")
+set(jp_mods "${input_mods}")
 if(TOMBA_JP_ENHANCEMENTS)
     find_package(Python3 REQUIRED COMPONENTS Interpreter)
     get_filename_component(jp_generated "${TOMBA_JP_GENERATED_DIR}" DIRECTORY)
@@ -57,3 +60,5 @@ endif()
 # The shared launcher already embeds the UTF-8 application manifest
 # (recomp-ui windows/recomp_utf8.manifest); a second manifest resource would
 # collide with it at link time.
+
+target_sources(tomba-jp PRIVATE "${TOMBA_ROOT}/src/mods/tomba_low_input_latency_plugin.c")

jp/game.toml

@@ -17,6 +17,7 @@ known_md5 = ["788922f281da3337e03c7113f9bd9bf5"]
 known_sha1 = ["c86baf702303e7e0963b99aff307b1c40e40478a"]
 
 [recompiler]
+mod_instruction_sites = ["0x800207C8"]
 seeds = "seeds/boot.txt"
 out_dir = "../build-jp/generated"
 strict = true