mirror of https://github.com/nmlgc/ReC98.git
[Reverse-engineering] [th05] Player shot cycle bitflags
A TH05 innovation that actually makes the game code easier to read?! Although it was quite hard to actually reverse-engineer it, with the confusing flag ordering pointing to some deeper meaning behind the flags, which really doesn't exist. Completes P0036, funded by zorg.
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nmlgc
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@ -1,3 +1,45 @@
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## Signedness
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|-|-|
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| `MOV al, var`<br />`MOV ah, 0`| `var` is *unsigned char* |
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## Arithmetic
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|-|-|
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| `ADD [m8], imm8` | Only achievable through a C++ method operating on a member? |
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| `MOV AL, [m8]`<br />`ADD AL, imm8`<br />`MOV [m8], AL` | Opposite; *not* an inlined function |
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### Arithmetic on a register *after* assigning it to a variable?
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Assigment is part of the C expression. If it's a comparison, that comparison
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must be spelled out to silence the `Possibly incorrect assignment` warning.
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|-|-|
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| `CALL somefunc`<br />`MOV ??, AX`<br />`OR AX, AX`<br />`JNZ ↑` | `while(( ?? = somefunc() ) != NULL)` |
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### `SUB ??, imm` vs. `ADD ??, -imm`
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`SUB` means that `??` is unsigned. Might require suffixing `imm` with `u` in
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case it's part of an arithmetic expression that was promoted to `int`.
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## `switch` statements
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* Sequence of the individual cases is identical in both C and ASM
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* Multiple cases with the same offset in the table, to code that doesn't
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return? Code was compiled with `-O`
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## Inlining
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Always worth a try to get rid of a potential macro. Some edge cases don't
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inline optimally though:
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* Assignments to a pointer in `SI` – that pointer is moved to `DI`,
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[clobbering that register](#clobbering-di). Try a [class method](#C++)
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instead.
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## C++
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* Every class method that returns `*this` inlines to the ideal representation.
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@ -0,0 +1,56 @@
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public SHOT_CYCLE_INIT
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shot_cycle_init proc near
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@@cycle_flag = byte ptr [bp-1]
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enter 2, 0
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mov @@cycle_flag, 0
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mov al, _shot_time
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mov ah, 0
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sub ax, 3
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mov bx, ax
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cmp bx, 15
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ja short @@cycle____
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add bx, bx
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jmp word ptr cs:@@time_to_cycle[bx]
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@@cycle6321:
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mov @@cycle_flag, SC_6X or SC_3X or SC_2X or SC_1X
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jmp short @@snd
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@@cycle6_2_:
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mov @@cycle_flag, SC_6X or SC_2X
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jmp short @@in_a_cycle
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@@cycle63__:
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mov @@cycle_flag, SC_6X or SC_3X
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@@snd:
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call snd_se_play pascal, 1
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jmp short @@in_a_cycle
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@@cycle6___:
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mov @@cycle_flag, SC_6X
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jmp short @@in_a_cycle
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@@cycle____:
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mov al, 0
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leave
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retn
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@@in_a_cycle:
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mov _shot_ptr, offset _shots
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mov _shot_last_id, 0
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mov al, @@cycle_flag
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leave
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retn
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db 0
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@@time_to_cycle label word
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dw @@cycle6___, @@cycle____, @@cycle____
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dw @@cycle63__, @@cycle____, @@cycle____
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dw @@cycle6_2_, @@cycle____, @@cycle____
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dw @@cycle63__, @@cycle____, @@cycle____
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dw @@cycle6___, @@cycle____, @@cycle____
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dw @@cycle6321
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shot_cycle_init endp
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@ -11,6 +11,22 @@
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bb_seg_t pascal near bb_load(const char far *fn);
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/// -------
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/// Player
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/// ------
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// Shots
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// -----
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// Shot cycle bitflags
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#define SC_1X 0x8 // Triggered 1× per cycle
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#define SC_2X 0x2 // Triggered 2× per cycle
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#define SC_3X 0x1 // Triggered 3× per cycle
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#define SC_6X 0x4 // Triggered 6× per cycle
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// Returns the current shot cycle, and prepares everything for more shots
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// being added.
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char pascal near shot_cycle_init(void);
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// -----
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/// ------
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/// Stages
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/// ------
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void pascal near stage2_update(void);
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@ -2,6 +2,11 @@ GAME = 5
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include th04/shared.inc
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include th05/player/shot_types.inc
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; Shot cycle bitflags
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SC_1X = 08h ; Triggered 1× per cycle
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SC_2X = 02h ; Triggered 2× per cycle
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SC_3X = 01h ; Triggered 3× per cycle
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SC_6X = 04h ; Triggered 6× per cycle
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_player_option_patnum = 26
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144
th05_main.asm
144
th05_main.asm
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@ -13640,81 +13640,7 @@ loc_128FA:
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retf
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sub_12842 endp
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; =============== S U B R O U T I N E =======================================
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; Attributes: bp-based frame
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sub_12914 proc near
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var_1 = byte ptr -1
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enter 2, 0
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mov [bp+var_1], 0
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mov al, _shot_time
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mov ah, 0
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sub ax, 3
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mov bx, ax
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cmp bx, 0Fh
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ja short loc_12951
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add bx, bx
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jmp word ptr cs:table_12966[bx]
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loc_12932:
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mov [bp+var_1], 0Fh
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jmp short loc_12942
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; ---------------------------------------------------------------------------
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loc_12938:
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mov [bp+var_1], 6
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jmp short loc_12955
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; ---------------------------------------------------------------------------
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loc_1293E:
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mov [bp+var_1], 5
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loc_12942:
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call snd_se_play pascal, 1
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jmp short loc_12955
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; ---------------------------------------------------------------------------
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loc_1294B:
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mov [bp+var_1], 4
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jmp short loc_12955
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; ---------------------------------------------------------------------------
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loc_12951:
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mov al, 0
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leave
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retn
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; ---------------------------------------------------------------------------
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loc_12955:
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mov _shot_ptr, offset _shots
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mov _shot_last_id, 0
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mov al, [bp+var_1]
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leave
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retn
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sub_12914 endp
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; ---------------------------------------------------------------------------
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db 0
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table_12966 dw loc_1294B
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dw loc_12951
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dw loc_12951
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dw loc_1293E
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dw loc_12951
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dw loc_12951
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dw loc_12938
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dw loc_12951
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dw loc_12951
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dw loc_1293E
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dw loc_12951
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dw loc_12951
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dw loc_1294B
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dw loc_12951
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dw loc_12951
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dw loc_12932
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include th05/player/shot_cycle_init.asm
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; =============== S U B R O U T I N E =======================================
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@ -13724,7 +13650,7 @@ shot_l0 proc near
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push bp
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mov bp, sp
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push si
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call sub_12914
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call shot_cycle_init
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test al, 1
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jz short loc_1299E
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call shots_add
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@ -13748,7 +13674,7 @@ shot_l1 proc near
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push bp
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mov bp, sp
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push si
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call sub_12914
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call shot_cycle_init
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test al, 1
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jz short loc_129C8
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call shots_add
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@ -13779,7 +13705,7 @@ shot_reimu_l2 proc near
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enter 2, 0
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push si
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mov byte ptr [bp-1], 1
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call sub_12914
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call shot_cycle_init
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test al, 9
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jz short loc_12A49
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test al, 8
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@ -13853,7 +13779,7 @@ shot_reimu_l3 proc near
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enter 2, 0
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push si
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mov byte ptr [bp-1], 2
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call sub_12914
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call shot_cycle_init
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test al, 9
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jz short loc_12ACD
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test al, 8
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@ -13930,7 +13856,7 @@ shot_reimu_l4 proc near
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enter 2, 0
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push si
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mov byte ptr [bp-1], 3
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call sub_12914
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call shot_cycle_init
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test al, 9
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jz short loc_12B51
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test al, 8
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@ -14005,7 +13931,7 @@ shot_reimu_l5 proc near
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enter 4, 0
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push si
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mov byte ptr [bp-1], 3
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call sub_12914
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call shot_cycle_init
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test al, 3
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jz loc_12BEE
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test al, 2
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@ -14091,7 +14017,7 @@ shot_reimu_l6 proc near
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enter 4, 0
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push si
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mov byte ptr [bp-1], 3
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call sub_12914
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call shot_cycle_init
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test al, 3
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jz loc_12C8B
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test al, 2
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@ -14177,7 +14103,7 @@ shot_reimu_l7 proc near
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enter 4, 0
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push si
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mov byte ptr [bp-1], 5
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call sub_12914
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call shot_cycle_init
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test al, 3
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jz loc_12D28
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test al, 2
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@ -14263,7 +14189,7 @@ shot_reimu_l8 proc near
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enter 2, 0
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push si
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mov byte ptr [bp-1], 7
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call sub_12914
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call shot_cycle_init
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test al, 1
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jnz short loc_12DA0
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jmp short loc_12DA9
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@ -14338,7 +14264,7 @@ shot_reimu_l9 proc near
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enter 4, 0
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push si
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mov byte ptr [bp-1], 7
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call sub_12914
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call shot_cycle_init
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test al, 3
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jz loc_12E5F
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test al, 2
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@ -14437,7 +14363,7 @@ var_1 = byte ptr -1
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enter 2, 0
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push si
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mov [bp+var_1], 1
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call sub_12914
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call shot_cycle_init
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test al, 9
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jz short loc_12EE1
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test al, 8
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@ -14512,7 +14438,7 @@ var_1 = byte ptr -1
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enter 2, 0
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push si
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mov [bp+var_1], 2
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call sub_12914
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call shot_cycle_init
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test al, 9
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jz loc_12F94
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test al, 8
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@ -14619,7 +14545,7 @@ var_2 = word ptr -2
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enter 2, 0
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push si
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mov byte ptr [bp+var_2+1], 3
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call sub_12914
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call shot_cycle_init
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test al, 9
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jz loc_1308E
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test al, 8
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@ -14746,7 +14672,7 @@ var_2 = word ptr -2
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enter 2, 0
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push si
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mov byte ptr [bp+var_2+1], 3
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call sub_12914
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call shot_cycle_init
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test al, 9
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jz loc_13195
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test al, 8
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@ -14877,7 +14803,7 @@ var_1 = byte ptr -1
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push si
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push di
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mov [bp+var_1], 4
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call sub_12914
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call shot_cycle_init
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test al, 9
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jz loc_1329E
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test al, 8
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@ -15017,7 +14943,7 @@ var_1 = byte ptr -1
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push si
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push di
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mov [bp+var_1], 4
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call sub_12914
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call shot_cycle_init
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test al, 9
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jz loc_133D8
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test al, 8
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@ -15175,7 +15101,7 @@ var_1 = byte ptr -1
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push si
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push di
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mov [bp+var_1], 4
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call sub_12914
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call shot_cycle_init
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test al, 9
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jz loc_13516
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test al, 8
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@ -15333,7 +15259,7 @@ var_1 = byte ptr -1
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push si
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push di
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mov [bp+var_1], 6
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call sub_12914
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call shot_cycle_init
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test al, 9
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jz loc_13697
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test al, 8
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@ -15522,7 +15448,7 @@ var_1 = byte ptr -1
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enter 2, 0
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push si
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mov [bp+var_1], 2
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call sub_12914
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call shot_cycle_init
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test al, 5
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jz short loc_13720
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test al, 1
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@ -15591,7 +15517,7 @@ var_1 = byte ptr -1
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enter 2, 0
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push si
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mov [bp+var_1], 2
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call sub_12914
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call shot_cycle_init
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test al, 5
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jz short loc_13798
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test al, 1
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@ -15666,7 +15592,7 @@ var_1 = byte ptr -1
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enter 2, 0
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push si
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mov [bp+var_1], 4
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call sub_12914
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call shot_cycle_init
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test al, 5
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jz short loc_13828
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test al, 1
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@ -15761,7 +15687,7 @@ var_2 = word ptr -2
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enter 2, 0
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push si
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mov byte ptr [bp+var_2+1], 4
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call sub_12914
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call shot_cycle_init
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test al, 5
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jz short loc_138C0
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test al, 1
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@ -15854,7 +15780,7 @@ var_2 = word ptr -2
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enter 2, 0
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push si
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mov byte ptr [bp+var_2+1], 4
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call sub_12914
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call shot_cycle_init
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test al, 5
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jz loc_1396C
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test al, 1
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@ -15956,7 +15882,7 @@ var_2 = word ptr -2
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enter 2, 0
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push si
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mov byte ptr [bp+var_2+1], 6
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call sub_12914
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call shot_cycle_init
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test al, 5
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jz loc_13A1F
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test al, 1
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@ -16064,7 +15990,7 @@ var_2 = word ptr -2
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enter 2, 0
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push si
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mov byte ptr [bp+var_2+1], 6
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call sub_12914
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call shot_cycle_init
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test al, 5
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jz loc_13AE7
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test al, 1
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@ -16174,7 +16100,7 @@ var_2 = word ptr -2
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enter 2, 0
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push si
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mov byte ptr [bp+var_2+1], 6
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call sub_12914
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call shot_cycle_init
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test al, 5
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jz loc_13BE8
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test al, 1
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@ -16320,7 +16246,7 @@ var_2 = word ptr -2
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enter 2, 0
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push si
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mov byte ptr [bp+var_2+1], 1
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call sub_12914
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call shot_cycle_init
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test al, 9
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jz short loc_13C74
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test al, 8
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@ -16394,7 +16320,7 @@ var_2 = word ptr -2
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enter 4, 0
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push si
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mov byte ptr [bp+var_2+1], 2
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call sub_12914
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call shot_cycle_init
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test al, 3
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jz short loc_13CFF
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test al, 2
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@ -16479,7 +16405,7 @@ var_2 = word ptr -2
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enter 4, 0
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push si
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mov byte ptr [bp+var_2+1], 3
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call sub_12914
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call shot_cycle_init
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test al, 3
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jz loc_13D9D
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test al, 2
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@ -16569,7 +16495,7 @@ var_2 = word ptr -2
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enter 4, 0
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push si
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mov byte ptr [bp+var_2+1], 3
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call sub_12914
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call shot_cycle_init
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test al, 3
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jz loc_13E53
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test al, 2
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@ -16680,7 +16606,7 @@ var_2 = word ptr -2
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enter 4, 0
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push si
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mov byte ptr [bp+var_2+1], 4
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call sub_12914
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call shot_cycle_init
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test al, 3
|
||||
jz loc_13F34
|
||||
test al, 2
|
||||
|
|
@ -16815,7 +16741,7 @@ var_2 = word ptr -2
|
|||
enter 4, 0
|
||||
push si
|
||||
mov byte ptr [bp+var_2+1], 4
|
||||
call sub_12914
|
||||
call shot_cycle_init
|
||||
test al, 3
|
||||
jz loc_14033
|
||||
test al, 2
|
||||
|
|
@ -16963,7 +16889,7 @@ var_2 = word ptr -2
|
|||
enter 4, 0
|
||||
push si
|
||||
mov byte ptr [bp+var_2+1], 5
|
||||
call sub_12914
|
||||
call shot_cycle_init
|
||||
test al, 3
|
||||
jz loc_14131
|
||||
test al, 2
|
||||
|
|
@ -17116,7 +17042,7 @@ var_2 = word ptr -2
|
|||
enter 4, 0
|
||||
push si
|
||||
mov byte ptr [bp+var_2+1], 5
|
||||
call sub_12914
|
||||
call shot_cycle_init
|
||||
test al, 3
|
||||
jz loc_14248
|
||||
test al, 2
|
||||
|
|
|
|||
Loading…
Reference in New Issue