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$include <elf.sail>
val read_register = "reg_deref" : forall ('a : Type). register('a) -> 'a effect {rreg}
// EL1 physical EL2 physical EL3 physical EL1 virtual, EL2 virtual
let CNT_CVAL = [ref CNTP_CVAL_EL0, ref CNTHP_CVAL_EL2, ref CNTPS_CVAL_EL1, ref CNTV_CVAL_EL0, ref CNTHV_CVAL_EL2]
let CNT_TVAL = [ref CNTP_TVAL_EL0, ref CNTHP_TVAL_EL2, ref CNTPS_TVAL_EL1, ref CNTV_TVAL_EL0, ref CNTHV_TVAL_EL2]
let CNT_CTL = [ref CNTP_CTL_EL0, ref CNTHP_CTL_EL2, ref CNTPS_CTL_EL1, ref CNTV_CTL_EL0, ref CNTHV_CTL_EL2 ]
let CNT_CTL = [ref CNTP_CTL_EL0, ref CNTHP_CTL_EL2, ref CNTPS_CTL_EL1, ref CNTV_CTL_EL0, ref CNTHV_CTL_EL2 ]
let CNT_IRQ = [0x0000_000d, 0x0000_000a, 0x0000_03ff, 0x0000_000b, 0x0000_03ff ]
// No IRQ No IRQ?
// SGI Interrupts are 0-15, PPI interrupts are 16-31, so SPI interrupts have an offset of 32.
let SPI_OFFSET = 32
// Simple top level fetch and execute loop.
val fetch_and_execute : unit -> unit effect {escape, undef, wreg, rreg, rmem, wmem}
function fetch_and_execute () = {
var cycle_counter : int = 0;
while true do {
cycle_counter = cycle_counter + 1;
try {
// Increment the counter
CNTPCT_EL0 = CNTPCT_EL0 + 1;
CNTVCT_EL0 = CNTPCT_EL0 - CNTVOFF_EL2;
// Timer value view for each timer
foreach (timer from 0 to 4) {
let TVAL = CNT_TVAL[timer];
let nextTVAL = read_register(TVAL) - 1;
(*TVAL) = nextTVAL;
if nextTVAL == 0x0000_0000 then {
_IRQPending = true;
AArch64_TakePhysicalIRQException()
}
};
// Handle the Kernel event stream, if enabled by CNTKCTL_EL1[2].
if CNTKCTL_EL1[2] == bitone then {
let mask = LSL(ZeroExtend(0x1, 64), UInt(CNTKCTL_EL1[7 .. 4]));
// Trigger event stream on either rising bit (0-1, bitzero) or falling (1-0, bitone)
let trigger : bool = if CNTKCTL_EL1[3] == bitzero then {
((CNTVCT_EL0 - 1) & mask) == Zeros() & (CNTVCT_EL0 & mask) != Zeros()
} else {
((CNTVCT_EL0 - 1) & mask) != Zeros() & (CNTVCT_EL0 & mask) == Zeros()
};
if trigger & PSTATE.I == bitzero then {
_IRQPending = true;
AArch64_TakePhysicalIRQException()
}
};
// Handle the Hypervisor event stream, if enabled by CNTHCTL_EL2[2].
if CNTHCTL_EL2[2] == bitone then {
let mask = LSL(ZeroExtend(0x1, 64), UInt(CNTHCTL_EL2[7 .. 4]));
// Trigger event stream on either rising bit (0-1, bitzero) or falling (1-0, bitone)
let trigger : bool = if CNTHCTL_EL2[3] == bitzero then {
((CNTPCT_EL0 - 1) & mask) == Zeros() & (CNTPCT_EL0 & mask) != Zeros()
} else {
((CNTPCT_EL0 - 1) & mask) != Zeros() & (CNTPCT_EL0 & mask) == Zeros()
};
if trigger & PSTATE.I == bitzero then {
prerr("[Clock] Tick\n");
_IRQPending = true;
AArch64_TakePhysicalIRQException()
}
};
var prevEL = PSTATE.EL;
var prevI = PSTATE.I;
// Store the old values of the Counter-timer Kernel/Hypervisor Control
// registers, as we want to figure out when they changes.
var prevCNTKCTL_EL1 = CNTKCTL_EL1;
var prevCNTHCTL_EL2 = CNTHCTL_EL2;
if ~(__Sleeping()) then {
// Check for pending interrupts
var interrupt_req : InterruptReq = undefined;
interrupt_req.take_SE = true; interrupt_req.take_vSE = true;
interrupt_req.take_IRQ = true; interrupt_req.take_vIRQ = true;
interrupt_req.take_FIQ = true; interrupt_req.take_vFIQ = true;
if TakePendingInterrupts(interrupt_req) then {
print("Pending interrupt taken\n");
} else {
var ok = false;
try {
__currentInstr = __fetchA64();
ok = true;
} catch {
Error_ExceptionTaken() => {
print(concat_str("Exception taken during IFetch from PC=", concat_str(HexStr(UInt(aget_PC())), "\n")));
},
_ => {
print("Exiting due to unhandled exception during fetch\n");
exit()
}
};
if ok then {
try {
ok = false;
__PC_changed = false;
ShouldAdvanceIT = (PSTATE.nRW == [bitone]) & (PSTATE.T == [bitone]);
decode(__currentInstr);
if ~(__PC_changed) then _PC = _PC + 4 else ();
if ShouldAdvanceIT then AArch32_ITAdvance() else ();
SSAdvance();
__UpdateSystemCounter(); // should this happen even if sleeping?
ok = true;
} catch {
Error_See(_) => UndefinedFault(),
Error_ReservedEncoding(_) => UndefinedFault(),
Error_Undefined() => UndefinedFault(),
Error_ExceptionTaken() => {
print(concat_str("Exception taken during Decode/Execute from PC=", concat_str(HexStr(UInt(aget_PC())), "\n")));
},
_ => {
print("Exiting due to unhandled exception during decode/execute\n");
exit()
}
}
};
if ~(ok) then {
print(concat_str("Yoiks: something went wrong at ", concat_str(DecStr(cycle_counter), "\n")));
}
}
};
// We want to keep track of what exception level we are in for debugging purposes.
if UInt(prevEL) > UInt(PSTATE.EL) then {
prerr_bits("[Sail] Exception level dropped to: ", PSTATE.EL)
};
if prevI != PSTATE.I then {
prerr_bits("[Sail] PSTATE.I changed to: ", PSTATE.I);
};
if prevCNTKCTL_EL1 != CNTKCTL_EL1 then {
prerr_bits("[Clock] CNTKCTL_EL1 changed to ", CNTKCTL_EL1);
};
if prevCNTHCTL_EL2 != CNTHCTL_EL2 then {
prerr_bits("[Clock] CNTHCTL_EL2 changed to ", CNTHCTL_EL2);
}
} catch {
Error_See(str) if str == "HINT" => (),
Error_ExceptionTaken(_) => {
// enable_tracing()
()
},
_ => {
prerr("Exiting due to unhandled exception\n");
exit()
}
};
__EndCycle()
}
}
let COLD_RESET : bool = true
val "load_raw" : (bits(64), string) -> unit
val init : unit -> unit effect {escape, undef, rreg, wreg}
function init() = {
__currentInstrLength = 4;
TakeReset(COLD_RESET);
_PC = CFG_RVBAR;
}
val main : unit -> unit effect {escape, undef, wreg, rreg, rmem, wmem}
function main() = {
init();
fetch_and_execute()
}
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