Fix Vita port and likely some Linux/Android hidden issues

Using an invalid SP makes Vita crash (for an unkown reason) and makes
things like C signal handlers crash (luckily Retroarch doesn't use
them). It is also a violation of the ABI and not a great idea.
Recycled some little used registers to free SP. Perf should be roughly
the same.

2 files changed, 15 insertions, 16 deletions

diff --git a/arm/arm_emit.h b/arm/arm_emit.h
index a6951c2..1432617 100644
--- a/arm/arm_emit.h
+++ b/arm/arm_emit.h
@@ -67,9 +67,10 @@ void execute_store_u32_safe(u32 address, u32 source);
 #define reg_a1          ARMREG_R1
 #define reg_a2          ARMREG_R2
 
+/* scratch0 is shared with flags, be careful! */
 #define reg_s0          ARMREG_R9
-#define reg_base        ARMREG_SP
-#define reg_flags       ARMREG_R11
+#define reg_base        ARMREG_R11
+#define reg_flags       ARMREG_R9
 
 #define reg_cycles      ARMREG_R12
 
@@ -110,6 +111,7 @@ void execute_store_u32_safe(u32 address, u32 source);
 #define reg_x5         ARMREG_R8
 
 #define mem_reg        (~0U)
+#define save1_reg      21
 
 /*
 
@@ -1415,7 +1417,6 @@ u32 execute_store_cpsr_body(u32 _cpsr, u32 store_mask, u32 address)
 #define arm_block_memory_adjust_pc_load()                                     \
   if(reg_list & 0x8000)                                                       \
   {                                                                           \
-    generate_mov(reg_a0, reg_rv);                                             \
     generate_indirect_branch_arm();                                           \
   }                                                                           \
 
@@ -1463,12 +1464,14 @@ u32 execute_store_cpsr_body(u32 _cpsr, u32 store_mask, u32 address)
   arm_block_memory_offset_##offset_type();                                    \
   arm_block_memory_writeback_##access_type(writeback_type);                   \
   ARM_BIC_REG_IMM(0, reg_s0, reg_s0, 0x03, 0);                                \
+  generate_store_reg(reg_s0, save1_reg);                                      \
                                                                               \
   for(i = 0; i < 16; i++)                                                     \
   {                                                                           \
     if((reg_list >> i) & 0x01)                                                \
     {                                                                         \
       cycle_count++;                                                          \
+      generate_load_reg(reg_s0, save1_reg);                                   \
       generate_add_reg_reg_imm(reg_a0, reg_s0, offset, 0);                    \
       if(reg_list & ~((2 << i) - 1))                                          \
       {                                                                       \
@@ -1493,12 +1496,12 @@ u32 execute_store_cpsr_body(u32 _cpsr, u32 store_mask, u32 address)
   generate_load_reg(reg_a0, rn);                                              \
   generate_function_call(execute_load_##type);                                \
   write32((pc + 8));                                                          \
-  generate_mov(reg_s0, reg_rv);                                               \
+  generate_mov(reg_a2, reg_rv);                                               \
   generate_load_reg(reg_a0, rn);                                              \
   generate_load_reg(reg_a1, rm);                                              \
+  generate_store_reg(reg_a2, rd);                                             \
   generate_function_call(execute_store_##type);                               \
   write32((pc + 4));                                                          \
-  generate_store_reg(reg_s0, rd);                                             \
 }                                                                             \
 
 
@@ -1729,13 +1732,14 @@ u32 execute_store_cpsr_body(u32 _cpsr, u32 store_mask, u32 address)
 #define thumb_block_memory_extra_down()                                       \
 
 #define thumb_block_memory_extra_pop_pc()                                     \
+  generate_load_reg(reg_s0, save1_reg);                                       \
   generate_add_reg_reg_imm(reg_a0, reg_s0, (bit_count[reg_list] * 4), 0);     \
   generate_function_call(execute_load_u32);                                   \
   write32((pc + 4));                                                          \
-  generate_mov(reg_a0, reg_rv);                                               \
   generate_indirect_branch_cycle_update(thumb)                                \
 
 #define thumb_block_memory_extra_push_lr(base_reg)                            \
+  generate_load_reg(reg_s0, save1_reg);                                       \
   generate_add_reg_reg_imm(reg_a0, reg_s0, (bit_count[reg_list] * 4), 0);     \
   generate_load_reg(reg_a1, REG_LR);                                          \
   generate_function_call(execute_store_u32_safe)                              \
@@ -1782,12 +1786,14 @@ u32 execute_store_cpsr_body(u32 _cpsr, u32 store_mask, u32 address)
   ARM_BIC_REG_IMM(0, reg_s0, reg_s0, 0x03, 0);                                \
   thumb_block_address_preadjust_##pre_op();                                   \
   thumb_block_address_postadjust_##post_op(base_reg);                         \
+  generate_store_reg(reg_s0, save1_reg);                                      \
                                                                               \
   for(i = 0; i < 8; i++)                                                      \
   {                                                                           \
     if((reg_list >> i) & 0x01)                                                \
     {                                                                         \
       cycle_count++;                                                          \
+      generate_load_reg(reg_s0, save1_reg);                                   \
       generate_add_reg_reg_imm(reg_a0, reg_s0, offset, 0);                    \
       if(reg_list & ~((2 << i) - 1))                                          \
       {                                                                       \
diff --git a/arm/arm_stub.S b/arm/arm_stub.S
index b8651cf..944d36a 100644
--- a/arm/arm_stub.S
+++ b/arm/arm_stub.S
@@ -45,15 +45,14 @@ _##symbol:
 #define CHANGED_PC_STATUS (31 * 4)
 #define COMPLETED_FRAME   (32 * 4)
 #define OAM_UPDATED       (33 * 4)
-#define MAIN_THREAD_SP    (34 * 4)
 
 #define reg_a0            r0
 #define reg_a1            r1
 #define reg_a2            r2
 
 #define reg_s0            r9
-#define reg_base          sp
-#define reg_flags         r11
+#define reg_base          r11
+#define reg_flags         r9
 
 #define reg_cycles        r12
 
@@ -151,11 +150,9 @@ _##symbol:
 @ registers which are important to the dynarec.
 
 #define call_c_function(function)                                            ;\
-  ldr sp, [reg_base, #MAIN_THREAD_SP]                                        ;\
   stmdb sp!, { call_c_saved_regs }                                           ;\
   bl function                                                                ;\
   ldmia sp!, { call_c_saved_regs }                                           ;\
-  ldr sp, =reg                                                               ;\
 
 @ Jumps to PC (ARM or Thumb modes)
 @ This is really two functions/routines in one
@@ -483,9 +480,7 @@ defsymbl(execute_arm_translate)
   @ save the registers to be able to return later
   stmdb sp!, { r4, r5, r6, r7, r8, r9, r10, r11, r12, lr }
 
-  ldr r1, =reg                            @ reg to r1
-  str sp, [r1, #MAIN_THREAD_SP]           @ store the current sp
-  ldr sp, =reg                            @ reg_base = sp (loading addr)
+  ldr reg_base, =reg                      @ init base_reg
 
   mvn reg_cycles, r0                      @ load cycle counter
 
@@ -515,8 +510,6 @@ defsymbl(execute_arm_translate)
 @ Epilogue to return to the main thread (whatever called execute_arm_translate)
 
 return_to_main:
-  @ restore the stack pointer
-  ldr sp, [reg_base, #MAIN_THREAD_SP]
   @ restore the saved regs and return
   ldmia sp!, { r4, r5, r6, r7, r8, r9, r10, r11, r12, lr }
   bx lr