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authorDavid Guillen Fandos2021-03-05 17:47:20 +0100
committerDavid Guillen Fandos2021-03-05 17:47:20 +0100
commitd21478e06edb61d2f0565c06fc6665799a6d7e72 (patch)
tree0de4a2cd1bb233b1c100c204c7afd7e1f8be0564
parent7bebd3051c8723f785263f074ac5b180a9cc0852 (diff)
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ARM dynarec: Do not use the stack at all
Fix a C func call while at it. This is a prerequisite to make the dynarec re-entrant and get rid of libco
-rw-r--r--arm/arm_stub.S19
1 files changed, 15 insertions, 4 deletions
diff --git a/arm/arm_stub.S b/arm/arm_stub.S
index 687aacf..0de4cb4 100644
--- a/arm/arm_stub.S
+++ b/arm/arm_stub.S
@@ -40,6 +40,8 @@
#define CPU_HALT_STATE (30 * 4)
#define CHANGED_PC_STATUS (31 * 4)
+#define REG_HOST_SP (32 * 4)
+
#define reg_a0 r0
#define reg_a1 r1
@@ -141,13 +143,15 @@
@ Align the stack to 64 bits (ABIs that don't require it, still recommend so)
#define call_c_saved_regs r2, r3, r12, lr
-@ Calls a C function - all caller save registers which are important to the
-@ dynarec and to returning from this function are saved.
+@ Calls a C function - reloads the stack pointer and saves all caller save
+@ registers which are important to the dynarec.
#define call_c_function(function) ;\
+ ldr sp, [reg_base, #REG_HOST_SP] ;\
stmdb sp!, { call_c_saved_regs } ;\
bl function ;\
ldmia sp!, { call_c_saved_regs } ;\
+ ldr sp, =base_reg_area ;\
@ Update the GBA hardware (video, sound, input, etc)
@@ -475,7 +479,9 @@ execute_swi_function_builder(div, thumb)
.globl _execute_arm_translate
execute_arm_translate:
_execute_arm_translate:
- sub sp, sp, #0x100 @ allocate room for register data
+ ldr r1, =base_reg_area @ base_reg_area to r1
+ str sp, [r1, #REG_HOST_SP] @ store the current sp
+ ldr sp, =base_reg_area @ reg_base = sp (loading addr)
mvn reg_cycles, r0 @ load cycle counter
@@ -603,7 +609,7 @@ write_epilogue:
store_registers_arm() @ save ARM registers
3:
- bl update_gba @ update GBA until CPU isn't halted
+ call_c_function(update_gba) @ update GBA until CPU isn't halted
mvn reg_cycles, r0 @ load new cycle count
ldr r0, [reg_base, #REG_PC] @ load new PC
@@ -727,3 +733,8 @@ execute_load_builder(u32, 32, ldrne, #0xF0000000)
.comm memory_map_read 0x8000
.comm memory_map_write 0x8000
+.data
+
+base_reg_area:
+ .space 0x100, 0
+