improve pcsx force overlay script to load playable stages

build/pcsx-redux_scripts/force-overlay-load-on-boot.lua

@@ -1,27 +1,36 @@
 jit.off()
 
--- local overlay = 's19br'
+-- local overlay = 'abst'    -- load save from memcard
--- local overlay = 'abst'
+-- local overlay = 'brf'     -- briefing
--- local overlay = 'brf'
+-- local overlay = 'camera'  -- load jpeg from memcard
--- local overlay = 'camera'
+-- local overlay = 'change'  -- disc change
-local overlay = 'change'
+-- local overlay = 'demosel' -- demo theater
--- local overlay = 'd00a'
--- local overlay = 'd01a'
--- local overlay = 'd03a'
--- local overlay = 'd11c'
--- local overlay = 'd16e'
--- local overlay = 'd18a'
--- local overlay = 'd18ar'
--- local overlay = 'demosel'
 -- local overlay = 'ending'
 -- local overlay = 'endingr'
--- local overlay = 'opening'
+-- local overlay = 'opening' -- intro 'fmv'
--- local overlay = 'option'
+-- local overlay = 'option'  -- options
--- local overlay = 'preope'
+-- local overlay = 'preope'  -- previous operations
--- local overlay = 'rank'
+-- local overlay = 'rank'    -- end game rank
--- local overlay = 'roll'
+-- local overlay = 'roll'    -- credits
--- local overlay = 's00a'
+-- local overlay = 'select'  -- debug menu
--- local overlay = 's01a'
+-- local overlay = 'select1' -- debug menu stage select
+-- local overlay = 'select2' -- debug menu stage select S05A-S09A
+-- local overlay = 'select3' -- debug menu stage select S10A-S14E1
+-- local overlay = 'select4' -- debug menu stage select S15A-S20A
+-- local overlay = 'selectd' -- debug menu demo select
+-- local overlay = 'sound'   -- debug menu sound test
+-- local overlay = 'title'   -- konami logo and title screen
+
+-- local overlay = 'd00a'    -- docks cutscene
+-- local overlay = 'd01a'    -- helipad cutscene
+-- local overlay = 'd03a'    -- "s003c0.dmo"
+-- local overlay = 'd11c'    -- elevator cutscene
+-- local overlay = 'd16e'    -- rex cutscene
+-- local overlay = 'd18a'    -- end tunnel cutscene?
+-- local overlay = 'd18ar'   -- same as above? otacon/meryl versions?
+
+-- local overlay = 's00a'    -- docks
+-- local overlay = 's01a'    -- heliport
 -- local overlay = 's02a'
 -- local overlay = 's02b'
 -- local overlay = 's02c'
@@ -72,7 +81,7 @@ local overlay = 'change'
 -- local overlay = 's15b'
 -- local overlay = 's15c'
 -- local overlay = 's16a'
--- local overlay = 's16b'
+local overlay = 's16b'    -- smallest playable stage
 -- local overlay = 's16c'
 -- local overlay = 's16d'
 -- local overlay = 's17a'
@@ -85,27 +94,45 @@ local overlay = 'change'
 -- local overlay = 's19br'
 -- local overlay = 's20a'
 -- local overlay = 's20ar'
--- local overlay = 'select'
+
--- local overlay = 'select1'
+local mem = PCSX.getMemPtr()
--- local overlay = 'select2'
+
--- local overlay = 'select3'
+local function u8(addr)
--- local overlay = 'select4'
+    addr = bit.band(addr, 0x1fffff)
--- local overlay = 'selectd'
+    local ptr = ffi.cast('uint8_t*', mem + addr)
--- local overlay = 'sound'
+    return ptr[0]
--- local overlay = 'title'
+end
+
+local function c_str(addr)
+    local str = ''
+    if str_ptr ~= 0 then
+        local i = 0
+        repeat
+            local byte = u8(addr + i)
+            if byte ~= 0 then
+                str = str .. string.char(byte)
+            end
+            i = i + 1
+        until byte == 0
+    end
+    return str
+end
 
 if loader_bp == nil then                                                                                                    
-    loader_bp = PCSX.addBreakpoint(0x800236E0, 'Exec', 4, 'loader', function()                                              
+    loader_bp = PCSX.addBreakpoint(0x8002E460, 'Exec', 4, 'loader', function()
        local regs = PCSX.getRegisters()                                                                                    
        local addr = bit.band(regs.GPR.n.a0, 0x1fffff)     
        local mem = PCSX.getMemPtr()
-       local ptr = ffi.cast('uint8_t*', mem + addr)                                                                        
+       local name =  c_str(regs.GPR.n.a0)
-       local i = 0
+       if name == 'title' then
-       for c in overlay:gmatch('.') do
+            local ptr = ffi.cast('uint8_t*', mem + addr)
-           ptr[i] = string.byte(c)
+            local i = 0
-           i = i + 1
+            for c in overlay:gmatch('.') do
+                ptr[i] = string.byte(c)
+                i = i + 1
+            end
+            ptr[i] = 0
+            print('forcing load of overlay:', overlay)
        end
-       ptr[i] = 0
-       print('forcing load of overlay:', overlay)
     end)                                                                                                                    
 end