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Predict TBR values based on elapsed virtual time.

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This commit is contained in:
Maxim Poliakovski 2021-12-20 00:12:44 +01:00
parent 087402290d
commit 7bdad7703c
1 changed files with 30 additions and 12 deletions
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42
cpu/ppc/ppcopcodes.cpp
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@ -858,6 +858,23 @@ void dppc_interpreter::ppc_mfspr() {
ppc_state.gpr[reg_d] = ppc_state.spr[ref_spr];
}
#define NS_PER_SEC 1E9
static inline uint64_t calc_tbr_value()
{
uint64_t diff = get_virt_time_ns() - tbr_wr_timestamp;
uint64_t tbr_inc = diff * tbr_freq_hz / NS_PER_SEC;
return (tbr_wr_value + tbr_inc);
}
static void update_timebase(uint64_t mask, uint64_t new_val)
{
uint64_t tbr_value = calc_tbr_value();
tbr_wr_value = (tbr_value & mask) | new_val;
tbr_wr_timestamp = get_virt_time_ns();
LOG_F(9, "New TBR value = 0x%llu", tbr_wr_value);
}
void dppc_interpreter::ppc_mtspr() {
uint32_t ref_spr = (((ppc_cur_instruction >> 11) & 31) << 5) | ((ppc_cur_instruction >> 16) & 31);
reg_s = (ppc_cur_instruction >> 21) & 31;
@ -877,13 +894,11 @@ void dppc_interpreter::ppc_mtspr() {
}
switch (ref_spr) {
// Mirror the TBRs in the SPR range to the user-mode TBRs.
case 284:
timebase_counter = (timebase_counter & 0xFFFFFFFF00000000ULL) + ppc_state.gpr[reg_s];
update_timebase(0xFFFFFFFF00000000ULL, ppc_state.gpr[reg_s]);
break;
case 285:
timebase_counter = (timebase_counter & 0x00000000FFFFFFFFULL) +
(((uint64_t)(ppc_state.gpr[reg_s])) << 32);
update_timebase(0x00000000FFFFFFFFULL, (uint64_t)(ppc_state.gpr[reg_s]) << 32);
break;
case 528:
case 529:
@ -910,15 +925,18 @@ void dppc_interpreter::ppc_mtspr() {
void dppc_interpreter::ppc_mftb() {
uint32_t ref_spr = (((ppc_cur_instruction >> 11) & 31) << 5) | ((ppc_cur_instruction >> 16) & 31);
reg_d = (ppc_cur_instruction >> 21) & 31;
uint64_t tbr_value = calc_tbr_value();
switch (ref_spr) {
case 268:
ppc_state.gpr[reg_d] = timebase_counter & 0xFFFFFFFFUL;
break;
case 269:
ppc_state.gpr[reg_d] = (timebase_counter >> 32) & 0xFFFFFFFFUL;
break;
default:
LOG_F(ERROR, "Invalid TBR access attempted !\n");
case 268:
ppc_state.gpr[reg_d] = tbr_value & 0xFFFFFFFFUL;
break;
case 269:
ppc_state.gpr[reg_d] = (tbr_value >> 32) & 0xFFFFFFFFUL;
break;
default:
ppc_exception_handler(Except_Type::EXC_PROGRAM, Exc_Cause::ILLEGAL_OP);
}
}