From ade2bed5149e817f8bea94b5d232899c60352888 Mon Sep 17 00:00:00 2001
From: twinaphex
Date: Fri, 12 Dec 2014 06:31:16 +0100
Subject: CPU interpreter - group Thumb opcode case ranges 0x20 - 0x27 together

---
 cpu.c | 27 ++++-----------------------
 1 file changed, 4 insertions(+), 23 deletions(-)

(limited to 'cpu.c')

diff --git a/cpu.c b/cpu.c
index 5e36c52..3362eaf 100644
--- a/cpu.c
+++ b/cpu.c
@@ -1656,6 +1656,7 @@ void execute_arm(u32 cycles)
   cpu_alert_type cpu_alert;
 
   u32 old_pc;
+  u32 thumb_opcode_val = 0, arm_opcode_val = 0;
 
   if(!pc_address_block)
     pc_address_block = load_gamepak_page(pc_region & 0x3FF);
@@ -3261,8 +3262,9 @@ thumb_loop:
        check_pc_region();                                                          
        pc &= ~0x01;                                                                
        opcode = address16(pc_address_block, (pc & 0x7FFF));                        
+       thumb_opcode_val = (opcode >> 8) & 0xFF;
 
-       switch((opcode >> 8) & 0xFF)                                                
+       switch(thumb_opcode_val)                                                
        {                                                                           
           case 0x00 ... 0x07:                                                       
              /* LSL rd, rs, offset */                                                
@@ -3301,42 +3303,21 @@ thumb_loop:
 
           case 0x20:                                                                
              /* MOV r0, imm */                                                       
-             thumb_logic(imm, 0, imm);                                               
-             break;                                                                  
-
           case 0x21:                                                                
              /* MOV r1, imm */                                                       
-             thumb_logic(imm, 1, imm);                                               
-             break;                                                                  
-
           case 0x22:                                                                
              /* MOV r2, imm */                                                       
-             thumb_logic(imm, 2, imm);                                               
-             break;                                                                  
-
           case 0x23:                                                                
              /* MOV r3, imm */                                                       
-             thumb_logic(imm, 3, imm);                                               
-             break;                                                                  
-
           case 0x24:                                                                
              /* MOV r4, imm */                                                       
-             thumb_logic(imm, 4, imm);                                               
-             break;                                                                  
-
           case 0x25:                                                                
              /* MOV r5, imm */                                                       
-             thumb_logic(imm, 5, imm);                                               
-             break;                                                                  
-
           case 0x26:                                                                
              /* MOV r6, imm */                                                       
-             thumb_logic(imm, 6, imm);                                               
-             break;                                                                  
-
           case 0x27:                                                                
              /* MOV r7, imm */                                                       
-             thumb_logic(imm, 7, imm);                                               
+             thumb_logic(imm, thumb_opcode_val - 0x20, imm);                                               
              break;                                                                  
 
           case 0x28:                                                                
-- 
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