Files
FEX-Emu--FEX/Source/Windows/ARM64EC/Module.S
T
Billy Laws 5dc85307a6 Windows: Introduce an initial ARM64EC frontend
This allows for running x64 applications under wine without having to run all
of wine under FEX. The JIT is invoked when ARM64EC code performs an indirect
branch to x64 code, and left whenever the x64 code calls into ARM64EC
code.
2024-07-12 18:07:50 +00:00

63 lines
2.0 KiB
ArmAsm

.text
.balign 16
// __os_arm64x_x64_jump in ARM64EC docs
// Expects target code address in x9
.globl DispatchJump
DispatchJump:
str lr, [sp, #-8]! // Push return address to stack, this will be popped by the x86 RET instr.
b check_target_ec
// __os_arm64x_dispatch_ret in ARM64EC docs
// Expects target code address in lr
.globl RetToEntryThunk
RetToEntryThunk:
mov x9, lr
check_target_ec:
// Check if target is in fact x86 code
ldr x16, [x18, #0x60] // TEB->PEB
ldr x16, [x16, #0x368] // PEB->EcCodeBitMap
lsr x17, x9, #15
and x17, x17, #0x1fffffffffff8
ldr x16, [x16, x17]
lsr x17, x9, #12
lsr x16, x16, x17
tbnz x16, #0, ExitFunctionEC
b enter_jit
// __os_arm64x_dispatch_call_no_redirect in ARM64EC docs
// Expects target code address in x9, and to be called using a 'blr x16' instruction.
.globl ExitToX64
ExitToX64:
str lr, [sp, #-8]! // Push return address to stack, this will be popped by the x86 RET instr.
enter_jit:
ldr x17, [x18, #0x1788] // TEB->ChpeV2CpuAreaInfo
ldr x16, [x17, #0x40] // ChpeV2CpuAreaInfo->EmulatorData[2] - DispatcherLoopTopEnterEC
br x16 // DispatcherLoopTopEnterEC(RIP:x9, CPUArea:x17)
// Called into by FEXCore
// Expects the target code address in x9
.global ExitFunctionEC
ExitFunctionEC:
// Either return to an exit thunk (return to ARM64EC function) or call an entry thunk (call to ARM64EC function).
// It is assumed that a 'blr x16' instruction is only ever used to call into x86 code from an exit thunk, and that all
// exported ARM64EC functions have a 4-byte offset to their entry thunk immediately before their first instruction.
mov x17, x9
mov w16, #0x200
movk w16, #0xd63f, lsl 16 // blr x16
ldursw x23, [x17, #-0x4] // Load either the entry thunk offset or the calling instruction.
cmp w23, w16
beq ret_sp_aligned
and x23, x23, #-0x4
add x17, x17, x23 // Resolve entry thunk address.
mov x4, sp
ldr lr, [x4], #0x8 // Pop the return address into lr.
mov sp, x4
ret_sp_aligned:
br x17