the abi sucks

Signed-off-by: lizzie <lizzie@eden-emu.dev>

src/dynarmic/src/dynarmic/backend/ppc64/abi.h

@@ -55,9 +55,16 @@ constexpr powah::GPR ABI_PARAM4 = powah::R6;
 
 // See https://refspecs.linuxfoundation.org/ELF/ppc64/PPC-elf64abi.html#REG
 constexpr std::initializer_list<u32> GPR_ORDER{
-    14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31
+    //6, 7, 8, 9, 10, 11, 12, //volatile
+    // r13 is thread-id
+    14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31 //non-volatile
 };
 
+constexpr std::initializer_list<powah::GPR> ABI_CALLEER_SAVED{
+    powah::R3, powah::R4, powah::R5, powah::R6,
+    powah::R7, powah::R8, powah::R9, powah::R10,
+    powah::R11, powah::R12
+};
 constexpr std::initializer_list<powah::GPR> ABI_CALLEE_SAVED{
     powah::R14, powah::R15, powah::R16, powah::R17,
     powah::R18, powah::R19, powah::R20, powah::R21,

src/dynarmic/src/dynarmic/backend/ppc64/emit_ppc64.cpp

@@ -20,6 +20,7 @@
 #include "dynarmic/ir/basic_block.h"
 #include "dynarmic/ir/microinstruction.h"
 #include "dynarmic/ir/opcodes.h"
+#include "stack_layout.h"
 
 namespace Dynarmic::Backend::PPC64 {
 
@@ -154,20 +155,16 @@ void EmitTerminal(powah::Context& code, EmitContext& ctx, IR::Term::ReturnToDisp
 }
 
 void EmitTerminal(powah::Context& code, EmitContext& ctx, IR::Term::LinkBlock terminal, IR::LocationDescriptor initial_location, bool) {
-    auto const tmp = ctx.reg_alloc.ScratchGpr();
     if (ctx.emit_conf.a64_variant) {
+        auto const tmp = ctx.reg_alloc.ScratchGpr();
         code.LI(tmp, terminal.next.Value());
         code.STD(tmp, PPC64::RJIT, offsetof(A64JitState, pc));
         code.LD(tmp, PPC64::RJIT, offsetof(A64JitState, run_fn));
         code.MTCTR(tmp);
-        for (u32 i = 0; i < 16; ++i)
-            code.STD(powah::GPR{14 + i}, powah::R1, -(offsetof(StackLayout, extra_regs) + (i * 8)));
-        code.ADDIS(powah::R1, powah::R1, -sizeof(StackLayout));
         code.BCTRL();
-        code.ADDI(powah::R1, powah::R1, sizeof(StackLayout));
-        for (u32 i = 0; i < 16; ++i)
-            code.LD(powah::GPR{14 + i}, powah::R1, -(offsetof(StackLayout, extra_regs) + (i * 8)));
+        code.LD(powah::R2, powah::R1, offsetof(StackLayout, sp));
     } else {
+        auto const tmp = ctx.reg_alloc.ScratchGpr();
         code.LI(tmp, terminal.next.Value());
         code.STW(tmp, PPC64::RJIT, offsetof(A32JitState, regs) + sizeof(u32) * 15);
         ASSERT(false && "unimp");
@@ -225,10 +222,14 @@ EmittedBlockInfo EmitPPC64(powah::Context& code, IR::Block block, const EmitConf
     auto const start_offset = code.offset;
     ebi.entry_point = &code.base[start_offset];
 
+    code.MFLR(powah::R0);
+    code.STD(powah::R0, powah::R1, offsetof(StackLayout, lr));
     // Non-volatile saves
-    std::vector<u32> gpr_order{GPR_ORDER};
-    for (size_t i = 0; i < gpr_order.size(); ++i)
-        code.STD(powah::GPR{gpr_order[i]}, powah::R1, -(i * 8));
+    std::vector<powah::GPR> abi_callee_saved{ABI_CALLEE_SAVED};
+    for (size_t i = 0; i < abi_callee_saved.size(); ++i)
+        code.STD(abi_callee_saved[i], powah::R1, -(8 + i * 8));
+    code.STDU(powah::R1, powah::R1, -sizeof(StackLayout));
+    code.STD(powah::R2, powah::R1, offsetof(StackLayout, sp));
 
     for (auto iter = block.begin(); iter != block.end(); ++iter) {
         IR::Inst* inst = &*iter;
@@ -257,8 +258,11 @@ EmittedBlockInfo EmitPPC64(powah::Context& code, IR::Block block, const EmitConf
     // auto const cycles_to_add = block.CycleCount();
     EmitTerminal(code, ctx, ctx.block.GetTerminal(), ctx.block.Location(), false);
 
-    for (size_t i = 0; i < gpr_order.size(); ++i)
-        code.LD(powah::GPR{gpr_order[i]}, powah::R1, -(i * 8));
+    code.ADDI(powah::R1, powah::R1, sizeof(StackLayout));
+    code.LD(powah::R0, powah::R1, offsetof(StackLayout, lr));
+    code.MTLR(powah::R0);
+    for (size_t i = 0; i < abi_callee_saved.size(); ++i)
+        code.LD(abi_callee_saved[i], powah::R1, -(8 + i * 8));
     code.BLR();
     code.ApplyRelocs();
 

src/dynarmic/src/dynarmic/backend/ppc64/stack_layout.h

@@ -12,11 +12,12 @@ namespace Dynarmic::Backend::PPC64 {
 constexpr size_t SpillCount = 16;
 
 struct alignas(16) StackLayout {
-    std::array<u64, 18> regs;
+    u64 resv0; //0
+    u64 resv1; //8
+    u64 lr; //16
+    u64 sp; //24
     std::array<u64, SpillCount> spill;
     u64 check_bit;
-    void* lr;
-    std::array<u64, 29> extra_regs;
 };
 
 static_assert(sizeof(StackLayout) % 16 == 0);