diff --git a/src/dynarmic/backend/arm64/a32_address_space.cpp b/src/dynarmic/backend/arm64/a32_address_space.cpp
index 84acde3f..8a630c93 100644
--- a/src/dynarmic/backend/arm64/a32_address_space.cpp
+++ b/src/dynarmic/backend/arm64/a32_address_space.cpp
@@ -226,6 +226,9 @@ void A32AddressSpace::EmitPrelude() {
         if (conf.page_table) {
             code.MOV(Xpagetable, mcl::bit_cast<u64>(conf.page_table));
         }
+        if (conf.fastmem_pointer) {
+            code.MOV(Xfastmem, mcl::bit_cast<u64>(conf.fastmem_pointer));
+        }
 
         if (conf.enable_cycle_counting) {
             code.BL(prelude_info.get_ticks_remaining);
@@ -255,6 +258,9 @@ void A32AddressSpace::EmitPrelude() {
         if (conf.page_table) {
             code.MOV(Xpagetable, mcl::bit_cast<u64>(conf.page_table));
         }
+        if (conf.fastmem_pointer) {
+            code.MOV(Xfastmem, mcl::bit_cast<u64>(conf.fastmem_pointer));
+        }
 
         if (conf.enable_cycle_counting) {
             code.MOV(Xticks, 1);
@@ -358,6 +364,11 @@ EmitConfig A32AddressSpace::GetEmitConfig() {
         .detect_misaligned_access_via_page_table = conf.detect_misaligned_access_via_page_table,
         .only_detect_misalignment_via_page_table_on_page_boundary = conf.only_detect_misalignment_via_page_table_on_page_boundary,
 
+        .fastmem_pointer = mcl::bit_cast<u64>(conf.fastmem_pointer),
+        .recompile_on_fastmem_failure = conf.recompile_on_fastmem_failure,
+        .fastmem_address_space_bits = 32,
+        .silently_mirror_fastmem = true,
+
         .wall_clock_cntpct = conf.wall_clock_cntpct,
         .enable_cycle_counting = conf.enable_cycle_counting,
 
diff --git a/src/dynarmic/backend/arm64/a64_address_space.cpp b/src/dynarmic/backend/arm64/a64_address_space.cpp
index 9731b341..a54ee345 100644
--- a/src/dynarmic/backend/arm64/a64_address_space.cpp
+++ b/src/dynarmic/backend/arm64/a64_address_space.cpp
@@ -406,6 +406,9 @@ void A64AddressSpace::EmitPrelude() {
         if (conf.page_table) {
             code.MOV(Xpagetable, mcl::bit_cast<u64>(conf.page_table));
         }
+        if (conf.fastmem_pointer) {
+            code.MOV(Xfastmem, mcl::bit_cast<u64>(conf.fastmem_pointer));
+        }
 
         if (conf.enable_cycle_counting) {
             code.BL(prelude_info.get_ticks_remaining);
@@ -434,6 +437,9 @@ void A64AddressSpace::EmitPrelude() {
         if (conf.page_table) {
             code.MOV(Xpagetable, mcl::bit_cast<u64>(conf.page_table));
         }
+        if (conf.fastmem_pointer) {
+            code.MOV(Xfastmem, mcl::bit_cast<u64>(conf.fastmem_pointer));
+        }
 
         if (conf.enable_cycle_counting) {
             code.MOV(Xticks, 1);
@@ -536,6 +542,11 @@ EmitConfig A64AddressSpace::GetEmitConfig() {
         .detect_misaligned_access_via_page_table = conf.detect_misaligned_access_via_page_table,
         .only_detect_misalignment_via_page_table_on_page_boundary = conf.only_detect_misalignment_via_page_table_on_page_boundary,
 
+        .fastmem_pointer = mcl::bit_cast<u64>(conf.fastmem_pointer),
+        .recompile_on_fastmem_failure = conf.recompile_on_fastmem_failure,
+        .fastmem_address_space_bits = conf.fastmem_address_space_bits,
+        .silently_mirror_fastmem = conf.silently_mirror_fastmem,
+
         .wall_clock_cntpct = conf.wall_clock_cntpct,
         .enable_cycle_counting = conf.enable_cycle_counting,
 
diff --git a/src/dynarmic/backend/arm64/address_space.cpp b/src/dynarmic/backend/arm64/address_space.cpp
index 2047df79..a314a419 100644
--- a/src/dynarmic/backend/arm64/address_space.cpp
+++ b/src/dynarmic/backend/arm64/address_space.cpp
@@ -300,13 +300,15 @@ FakeCall AddressSpace::FastmemCallback(u64 host_pc) {
             goto fail;
         }
 
+        const auto result = iter->second.fc;
+
         if (iter->second.recompile) {
             const auto marker = iter->second.marker;
             fastmem_manager.MarkDoNotFastmem(marker);
             InvalidateBasicBlocks({std::get<0>(marker)});
         }
 
-        return iter->second.fc;
+        return result;
     }
 
 fail:
diff --git a/src/dynarmic/backend/arm64/emit_arm64.h b/src/dynarmic/backend/arm64/emit_arm64.h
index 391193aa..c15d9266 100644
--- a/src/dynarmic/backend/arm64/emit_arm64.h
+++ b/src/dynarmic/backend/arm64/emit_arm64.h
@@ -128,6 +128,12 @@ struct EmitConfig {
     u8 detect_misaligned_access_via_page_table;
     bool only_detect_misalignment_via_page_table_on_page_boundary;
 
+    // Fastmem
+    u64 fastmem_pointer;
+    bool recompile_on_fastmem_failure;
+    size_t fastmem_address_space_bits;
+    bool silently_mirror_fastmem;
+
     // Timing
     bool wall_clock_cntpct;
     bool enable_cycle_counting;
diff --git a/src/dynarmic/backend/arm64/emit_arm64_memory.cpp b/src/dynarmic/backend/arm64/emit_arm64_memory.cpp
index 615022ab..1f36a7a0 100644
--- a/src/dynarmic/backend/arm64/emit_arm64_memory.cpp
+++ b/src/dynarmic/backend/arm64/emit_arm64_memory.cpp
@@ -5,13 +5,16 @@
 
 #include "dynarmic/backend/arm64/emit_arm64_memory.h"
 
+#include <optional>
 #include <utility>
 
+#include <mcl/bit_cast.hpp>
 #include <oaknut/oaknut.hpp>
 
 #include "dynarmic/backend/arm64/abi.h"
 #include "dynarmic/backend/arm64/emit_arm64.h"
 #include "dynarmic/backend/arm64/emit_context.h"
+#include "dynarmic/backend/arm64/fastmem.h"
 #include "dynarmic/backend/arm64/fpsr_manager.h"
 #include "dynarmic/backend/arm64/reg_alloc.h"
 #include "dynarmic/interface/halt_reason.h"
@@ -249,7 +252,7 @@ void EmitDetectMisalignedVAddr(oaknut::CodeGenerator& code, EmitContext& ctx, oa
 // Address to read/write = [ret0 + ret1], ret0 is always Xscratch0 and ret1 is either Xaddr or Xscratch1
 // Trashes NZCV
 template<size_t bitsize>
-std::pair<oaknut::XReg, oaknut::XReg> EmitVAddrLookup(oaknut::CodeGenerator& code, EmitContext& ctx, oaknut::XReg Xaddr, const SharedLabel& fallback) {
+std::pair<oaknut::XReg, oaknut::XReg> InlinePageTableEmitVAddrLookup(oaknut::CodeGenerator& code, EmitContext& ctx, oaknut::XReg Xaddr, const SharedLabel& fallback) {
     const size_t valid_page_index_bits = ctx.conf.page_table_address_space_bits - page_bits;
     const size_t unused_top_bits = 64 - ctx.conf.page_table_address_space_bits;
 
@@ -280,23 +283,26 @@ std::pair<oaknut::XReg, oaknut::XReg> EmitVAddrLookup(oaknut::CodeGenerator& cod
 }
 
 template<std::size_t bitsize>
-const void* EmitMemoryLdr(oaknut::CodeGenerator& code, int value_idx, oaknut::XReg Xbase, oaknut::XReg Xoffset, bool ordered) {
-    const void* fastmem_location = code.ptr<void*>();
+CodePtr EmitMemoryLdr(oaknut::CodeGenerator& code, int value_idx, oaknut::XReg Xbase, oaknut::XReg Xoffset, bool ordered, bool extend32 = false) {
+    const auto ext = extend32 ? oaknut::IndexExt::UXTW : oaknut::IndexExt::LSL;
+    const auto Roffset = extend32 ? oaknut::RReg{Xoffset.toW()} : oaknut::RReg{Xoffset};
+
+    const CodePtr fastmem_location = code.ptr<CodePtr>();
     switch (bitsize) {
     case 8:
-        code.LDRB(oaknut::WReg{value_idx}, Xbase, Xoffset);
+        code.LDRB(oaknut::WReg{value_idx}, Xbase, Roffset, ext);
         break;
     case 16:
-        code.LDRH(oaknut::WReg{value_idx}, Xbase, Xoffset);
+        code.LDRH(oaknut::WReg{value_idx}, Xbase, Roffset, ext);
         break;
     case 32:
-        code.LDR(oaknut::WReg{value_idx}, Xbase, Xoffset);
+        code.LDR(oaknut::WReg{value_idx}, Xbase, Roffset, ext);
         break;
     case 64:
-        code.LDR(oaknut::XReg{value_idx}, Xbase, Xoffset);
+        code.LDR(oaknut::XReg{value_idx}, Xbase, Roffset, ext);
         break;
     case 128:
-        code.LDR(oaknut::QReg{value_idx}, Xbase, Xoffset);
+        code.LDR(oaknut::QReg{value_idx}, Xbase, Roffset, ext);
         break;
     default:
         ASSERT_FALSE("Invalid bitsize");
@@ -311,28 +317,31 @@ const void* EmitMemoryLdr(oaknut::CodeGenerator& code, int value_idx, oaknut::XR
 }
 
 template<std::size_t bitsize>
-const void* EmitMemoryStr(oaknut::CodeGenerator& code, int value_idx, oaknut::XReg Xbase, oaknut::XReg Xoffset, bool ordered) {
+CodePtr EmitMemoryStr(oaknut::CodeGenerator& code, int value_idx, oaknut::XReg Xbase, oaknut::XReg Xoffset, bool ordered, bool extend32 = false) {
+    const auto ext = extend32 ? oaknut::IndexExt::UXTW : oaknut::IndexExt::LSL;
+    const auto Roffset = extend32 ? oaknut::RReg{Xoffset.toW()} : oaknut::RReg{Xoffset};
+
     if (ordered) {
         // TODO: Use STLR
         code.DMB(oaknut::BarrierOp::ISH);
     }
 
-    const void* fastmem_location = code.ptr<void*>();
+    const CodePtr fastmem_location = code.ptr<CodePtr>();
     switch (bitsize) {
     case 8:
-        code.STRB(oaknut::WReg{value_idx}, Xbase, Xoffset);
+        code.STRB(oaknut::WReg{value_idx}, Xbase, Roffset, ext);
         break;
     case 16:
-        code.STRH(oaknut::WReg{value_idx}, Xbase, Xoffset);
+        code.STRH(oaknut::WReg{value_idx}, Xbase, Roffset, ext);
         break;
     case 32:
-        code.STR(oaknut::WReg{value_idx}, Xbase, Xoffset);
+        code.STR(oaknut::WReg{value_idx}, Xbase, Roffset, ext);
         break;
     case 64:
-        code.STR(oaknut::XReg{value_idx}, Xbase, Xoffset);
+        code.STR(oaknut::XReg{value_idx}, Xbase, Roffset, ext);
         break;
     case 128:
-        code.STR(oaknut::QReg{value_idx}, Xbase, Xoffset);
+        code.STR(oaknut::QReg{value_idx}, Xbase, Roffset, ext);
         break;
     default:
         ASSERT_FALSE("Invalid bitsize");
@@ -364,7 +373,7 @@ void InlinePageTableEmitReadMemory(oaknut::CodeGenerator& code, EmitContext& ctx
 
     SharedLabel fallback = GenSharedLabel(), end = GenSharedLabel();
 
-    const auto [Xbase, Xoffset] = EmitVAddrLookup<bitsize>(code, ctx, Xaddr, fallback);
+    const auto [Xbase, Xoffset] = InlinePageTableEmitVAddrLookup<bitsize>(code, ctx, Xaddr, fallback);
     EmitMemoryLdr<bitsize>(code, Rvalue->index(), Xbase, Xoffset, ordered);
 
     ctx.deferred_emits.emplace_back([&code, &ctx, inst, Xaddr = *Xaddr, Rvalue = *Rvalue, ordered, fallback, end] {
@@ -404,7 +413,7 @@ void InlinePageTableEmitWriteMemory(oaknut::CodeGenerator& code, EmitContext& ct
 
     SharedLabel fallback = GenSharedLabel(), end = GenSharedLabel();
 
-    const auto [Xbase, Xoffset] = EmitVAddrLookup<bitsize>(code, ctx, Xaddr, fallback);
+    const auto [Xbase, Xoffset] = InlinePageTableEmitVAddrLookup<bitsize>(code, ctx, Xaddr, fallback);
     EmitMemoryStr<bitsize>(code, Rvalue->index(), Xbase, Xoffset, ordered);
 
     ctx.deferred_emits.emplace_back([&code, &ctx, inst, Xaddr = *Xaddr, Rvalue = *Rvalue, ordered, fallback, end] {
@@ -430,11 +439,155 @@ void InlinePageTableEmitWriteMemory(oaknut::CodeGenerator& code, EmitContext& ct
     code.l(*end);
 }
 
+std::optional<DoNotFastmemMarker> ShouldFastmem(EmitContext& ctx, IR::Inst* inst) {
+    if (!ctx.conf.fastmem_pointer || !ctx.fastmem.SupportsFastmem()) {
+        return std::nullopt;
+    }
+
+    const auto inst_offset = std::distance(ctx.block.begin(), IR::Block::iterator(inst));
+    const auto marker = std::make_tuple(ctx.block.Location(), inst_offset);
+    if (ctx.fastmem.ShouldFastmem(marker)) {
+        return marker;
+    }
+    return std::nullopt;
+}
+
+inline bool ShouldExt32(EmitContext& ctx) {
+    return ctx.conf.fastmem_address_space_bits == 32 && ctx.conf.silently_mirror_fastmem;
+}
+
+// May use Xscratch0 as scratch register
+// Address to read/write = [ret0 + ret1], ret0 is always Xfastmem and ret1 is either Xaddr or Xscratch0
+// Trashes NZCV
+template<size_t bitsize>
+std::pair<oaknut::XReg, oaknut::XReg> FastmemEmitVAddrLookup(oaknut::CodeGenerator& code, EmitContext& ctx, oaknut::XReg Xaddr, const SharedLabel& fallback) {
+    if (ctx.conf.fastmem_address_space_bits == 64 || ShouldExt32(ctx)) {
+        return std::make_pair(Xfastmem, Xaddr);
+    }
+
+    if (ctx.conf.silently_mirror_fastmem) {
+        code.UBFX(Xscratch0, Xaddr, 0, ctx.conf.fastmem_address_space_bits);
+        return std::make_pair(Xfastmem, Xscratch0);
+    }
+
+    code.LSR(Xscratch0, Xaddr, ctx.conf.fastmem_address_space_bits);
+    code.CBNZ(Xscratch0, *fallback);
+    return std::make_pair(Xfastmem, Xaddr);
+}
+
+template<size_t bitsize>
+void FastmemEmitReadMemory(oaknut::CodeGenerator& code, EmitContext& ctx, IR::Inst* inst, DoNotFastmemMarker marker) {
+    auto args = ctx.reg_alloc.GetArgumentInfo(inst);
+    auto Xaddr = ctx.reg_alloc.ReadX(args[1]);
+    auto Rvalue = [&] {
+        if constexpr (bitsize == 128) {
+            return ctx.reg_alloc.WriteQ(inst);
+        } else {
+            return ctx.reg_alloc.WriteReg<std::max<std::size_t>(bitsize, 32)>(inst);
+        }
+    }();
+    const bool ordered = IsOrdered(args[2].GetImmediateAccType());
+    ctx.fpsr.Spill();
+    ctx.reg_alloc.SpillFlags();
+    RegAlloc::Realize(Xaddr, Rvalue);
+
+    SharedLabel fallback = GenSharedLabel(), end = GenSharedLabel();
+
+    const auto [Xbase, Xoffset] = FastmemEmitVAddrLookup<bitsize>(code, ctx, Xaddr, fallback);
+    const auto fastmem_location = EmitMemoryLdr<bitsize>(code, Rvalue->index(), Xbase, Xoffset, ordered, ShouldExt32(ctx));
+
+    ctx.deferred_emits.emplace_back([&code, &ctx, inst, marker, Xaddr = *Xaddr, Rvalue = *Rvalue, ordered, fallback, end, fastmem_location] {
+        ctx.ebi.fastmem_patch_info.emplace(
+            fastmem_location - ctx.ebi.entry_point,
+            FastmemPatchInfo{
+                .marker = marker,
+                .fc = FakeCall{
+                    .call_pc = mcl::bit_cast<u64>(code.ptr<void*>()),
+                    .ret_pc = 0,
+                },
+                .recompile = ctx.conf.recompile_on_fastmem_failure,
+            });
+
+        code.l(*fallback);
+        code.MOV(Xscratch0, Xaddr);
+        EmitRelocation(code, ctx, WrappedReadMemoryLinkTarget(bitsize));
+        if (ordered) {
+            code.DMB(oaknut::BarrierOp::ISH);
+        }
+        if constexpr (bitsize == 128) {
+            code.MOV(Rvalue.B16(), Q0.B16());
+        } else {
+            code.MOV(Rvalue.toX(), Xscratch0);
+        }
+        ctx.conf.emit_check_memory_abort(code, ctx, inst, *end);
+        code.B(*end);
+    });
+
+    code.l(*end);
+}
+
+template<size_t bitsize>
+void FastmemEmitWriteMemory(oaknut::CodeGenerator& code, EmitContext& ctx, IR::Inst* inst, DoNotFastmemMarker marker) {
+    auto args = ctx.reg_alloc.GetArgumentInfo(inst);
+    auto Xaddr = ctx.reg_alloc.ReadX(args[1]);
+    auto Rvalue = [&] {
+        if constexpr (bitsize == 128) {
+            return ctx.reg_alloc.ReadQ(args[2]);
+        } else {
+            return ctx.reg_alloc.ReadReg<std::max<std::size_t>(bitsize, 32)>(args[2]);
+        }
+    }();
+    const bool ordered = IsOrdered(args[3].GetImmediateAccType());
+    ctx.fpsr.Spill();
+    ctx.reg_alloc.SpillFlags();
+    RegAlloc::Realize(Xaddr, Rvalue);
+
+    SharedLabel fallback = GenSharedLabel(), end = GenSharedLabel();
+
+    const auto [Xbase, Xoffset] = FastmemEmitVAddrLookup<bitsize>(code, ctx, Xaddr, fallback);
+    const auto fastmem_location = EmitMemoryStr<bitsize>(code, Rvalue->index(), Xbase, Xoffset, ordered, ShouldExt32(ctx));
+
+    ctx.deferred_emits.emplace_back([&code, &ctx, inst, marker, Xaddr = *Xaddr, Rvalue = *Rvalue, ordered, fallback, end, fastmem_location] {
+        ctx.ebi.fastmem_patch_info.emplace(
+            fastmem_location - ctx.ebi.entry_point,
+            FastmemPatchInfo{
+                .marker = marker,
+                .fc = FakeCall{
+                    .call_pc = mcl::bit_cast<u64>(code.ptr<void*>()),
+                    .ret_pc = 0,
+                },
+                .recompile = ctx.conf.recompile_on_fastmem_failure,
+            });
+
+        code.l(*fallback);
+        if constexpr (bitsize == 128) {
+            code.MOV(Xscratch0, Xaddr);
+            code.MOV(Q0.B16(), Rvalue.B16());
+        } else {
+            code.MOV(Xscratch0, Xaddr);
+            code.MOV(Xscratch1, Rvalue.toX());
+        }
+        if (ordered) {
+            code.DMB(oaknut::BarrierOp::ISH);
+        }
+        EmitRelocation(code, ctx, WrappedWriteMemoryLinkTarget(bitsize));
+        if (ordered) {
+            code.DMB(oaknut::BarrierOp::ISH);
+        }
+        ctx.conf.emit_check_memory_abort(code, ctx, inst, *end);
+        code.B(*end);
+    });
+
+    code.l(*end);
+}
+
 }  // namespace
 
 template<size_t bitsize>
 void EmitReadMemory(oaknut::CodeGenerator& code, EmitContext& ctx, IR::Inst* inst) {
-    if (ctx.conf.page_table_pointer != 0) {
+    if (const auto marker = ShouldFastmem(ctx, inst)) {
+        FastmemEmitReadMemory<bitsize>(code, ctx, inst, *marker);
+    } else if (ctx.conf.page_table_pointer != 0) {
         InlinePageTableEmitReadMemory<bitsize>(code, ctx, inst);
     } else {
         CallbackOnlyEmitReadMemory<bitsize>(code, ctx, inst);
@@ -448,7 +601,9 @@ void EmitExclusiveReadMemory(oaknut::CodeGenerator& code, EmitContext& ctx, IR::
 
 template<size_t bitsize>
 void EmitWriteMemory(oaknut::CodeGenerator& code, EmitContext& ctx, IR::Inst* inst) {
-    if (ctx.conf.page_table_pointer != 0) {
+    if (const auto marker = ShouldFastmem(ctx, inst)) {
+        FastmemEmitWriteMemory<bitsize>(code, ctx, inst, *marker);
+    } else if (ctx.conf.page_table_pointer != 0) {
         InlinePageTableEmitWriteMemory<bitsize>(code, ctx, inst);
     } else {
         CallbackOnlyEmitWriteMemory<bitsize>(code, ctx, inst);
diff --git a/src/dynarmic/backend/arm64/fastmem.h b/src/dynarmic/backend/arm64/fastmem.h
index fd6d91f7..3b98b056 100644
--- a/src/dynarmic/backend/arm64/fastmem.h
+++ b/src/dynarmic/backend/arm64/fastmem.h
@@ -36,8 +36,12 @@ public:
     explicit FastmemManager(ExceptionHandler& eh)
             : exception_handler(eh) {}
 
+    bool SupportsFastmem() const {
+        return exception_handler.SupportsFastmem();
+    }
+
     bool ShouldFastmem(DoNotFastmemMarker marker) const {
-        return exception_handler.SupportsFastmem() && do_not_fastmem.count(marker) == 0;
+        return do_not_fastmem.count(marker) == 0;
     }
 
     void MarkDoNotFastmem(DoNotFastmemMarker marker) {
diff --git a/src/dynarmic/backend/x64/emit_x64_memory.cpp.inc b/src/dynarmic/backend/x64/emit_x64_memory.cpp.inc
index ead088c3..4c807ed6 100644
--- a/src/dynarmic/backend/x64/emit_x64_memory.cpp.inc
+++ b/src/dynarmic/backend/x64/emit_x64_memory.cpp.inc
@@ -37,16 +37,18 @@ FakeCall AxxEmitX64::FastmemCallback(u64 rip_) {
         ASSERT_FALSE("iter != fastmem_patch_info.end()");
     }
 
+    FakeCall result{
+        .call_rip = iter->second.callback,
+        .ret_rip = iter->second.resume_rip,
+    };
+
     if (iter->second.recompile) {
         const auto marker = iter->second.marker;
         do_not_fastmem.emplace(marker);
         InvalidateBasicBlocks({std::get<0>(marker)});
     }
 
-    return FakeCall{
-        .call_rip = iter->second.callback,
-        .ret_rip = iter->second.resume_rip,
-    };
+    return result;
 }
 
 template<std::size_t bitsize, auto callback>