BRBFCR_EL1 Branch Record Buffer Function Control Register when FEAT_BRBE is implemented Functional controls for the Branch Record Buffer. BRBE BRBFCR_EL1 is a 64-bit register. 63 30 63:30 Reserved, RES0. BANK 29 28 29:28 Branch record buffer bank access control. All other values are reserved. 0b00 Select branch records 0 to 31. 0b01 Select branch records 32 to 63. AU 27 23 27:23 Reserved, RES0. CONDDIR 22 22 22 Match on conditional direct branch instructions. 0b0 Do not match on conditional direct branch instructions. 0b1 Match on conditional direct branch instructions. AU AU DIRCALL 21 21 21 Match on direct branch with link instructions. 0b0 Do not match on direct branch with link instructions. 0b1 Match on direct branch with link instructions. AU AU INDCALL 20 20 20 Match on indirect branch with link instructions. 0b0 Do not match on indirect branch with link instructions. 0b1 Match on indirect branch with link instructions. AU AU RTN 19 19 19 Match on function return instructions. 0b0 Do not match on function return instructions. 0b1 Match on function return instructions. AU AU INDIRECT 18 18 18 Match on indirect branch instructions. 0b0 Do not match on indirect branch instructions. 0b1 Match on indirect branch instructions. AU AU DIRECT 17 17 17 Match on unconditional direct branch instructions. 0b0 Do not match on unconditional direct branch instructions. 0b1 Match on unconditional direct branch instructions. AU AU EnI 16 16 16 Include or exclude matches. 0b0 Include records for matches, and exclude records for non-matches. 0b1 Exclude records for matches, and include records for non-matches. AU AU 15 8 15:8 Reserved, RES0. PAUSED 7 7 7 Branch recording Paused status. 0b0 Branch recording is not Paused. 0b1 Branch recording is Paused. AU AU 6 0 6:0 Reserved, RES0. MRS <Xt>, BRBFCR_EL1 if !IsFeatureImplemented(FEAT_BRBE) then Undefined(); elsif PSTATE.EL == EL0 then Undefined(); elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3().SBRBE != '11' && SCR_EL3().NS == '0' then Undefined(); elsif HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3().SBRBE IN {'x0'} && SCR_EL3().NS == '1' then Undefined(); elsif EL2Enabled() && IsFeatureImplemented(FEAT_FGT) && (!HaveEL(EL3) || SCR_EL3().FGTEn == '1') && HDFGRTR_EL2().nBRBCTL == '0' then AArch64_SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && MDCR_EL3().SBRBE != '11' && SCR_EL3().NS == '0' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; elsif HaveEL(EL3) && MDCR_EL3().SBRBE IN {'x0'} && SCR_EL3().NS == '1' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; else X{64}(t) = BRBFCR_EL1(); end; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3().SBRBE != '11' && SCR_EL3().NS == '0' then Undefined(); elsif HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3().SBRBE IN {'x0'} && SCR_EL3().NS == '1' then Undefined(); elsif HaveEL(EL3) && MDCR_EL3().SBRBE != '11' && SCR_EL3().NS == '0' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; elsif HaveEL(EL3) && MDCR_EL3().SBRBE IN {'x0'} && SCR_EL3().NS == '1' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; else X{64}(t) = BRBFCR_EL1(); end; elsif PSTATE.EL == EL3 then X{64}(t) = BRBFCR_EL1(); end; MSR BRBFCR_EL1, <Xt> if !IsFeatureImplemented(FEAT_BRBE) then Undefined(); elsif PSTATE.EL == EL0 then Undefined(); elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3().SBRBE != '11' && SCR_EL3().NS == '0' then Undefined(); elsif HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3().SBRBE IN {'x0'} && SCR_EL3().NS == '1' then Undefined(); elsif EL2Enabled() && IsFeatureImplemented(FEAT_FGT) && (!HaveEL(EL3) || SCR_EL3().FGTEn == '1') && HDFGWTR_EL2().nBRBCTL == '0' then AArch64_SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && MDCR_EL3().SBRBE != '11' && SCR_EL3().NS == '0' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; elsif HaveEL(EL3) && MDCR_EL3().SBRBE IN {'x0'} && SCR_EL3().NS == '1' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; else BRBFCR_EL1() = X{64}(t); end; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3().SBRBE != '11' && SCR_EL3().NS == '0' then Undefined(); elsif HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3().SBRBE IN {'x0'} && SCR_EL3().NS == '1' then Undefined(); elsif HaveEL(EL3) && MDCR_EL3().SBRBE != '11' && SCR_EL3().NS == '0' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; elsif HaveEL(EL3) && MDCR_EL3().SBRBE IN {'x0'} && SCR_EL3().NS == '1' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; else BRBFCR_EL1() = X{64}(t); end; elsif PSTATE.EL == EL3 then BRBFCR_EL1() = X{64}(t); end; 2026-03-26 20:27:25 2026-03_rel