MDSTEPOP

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MDSTEPOP_EL1, Monitor Debug Step Opcode Register

Purpose

Used to execute instructions while Software Step is in active-not-pending state.

Configuration

This register is present only when FEAT_STEP2 is implemented and FEAT_AA64 is implemented. Otherwise, direct accesses to MDSTEPOP_EL1 are UNDEFINED.

Attributes

Field descriptions

Bits [63:32]

OPCODE, bits [31:0]

Accessing MDSTEPOP_EL1

Accesses to this register use the following encodings in the System register encoding space:

MRS <Xt>, MDSTEPOP_EL1

op0	op1	CRn	CRm	op2
0b10	0b000	0b0000	0b0101	0b010

if !(IsFeatureImplemented(FEAT_STEP2) && IsFeatureImplemented(FEAT_AA64)) then Undefined(); elsif PSTATE.EL == EL0 then Undefined(); elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3().EnSTEPOP == '0' then Undefined(); elsif HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3().TDA == '1' then Undefined(); elsif EL2Enabled() && IsFeatureImplemented(FEAT_FGT2) && ((HaveEL(EL3) && SCR_EL3().FGTEn2 == '0') || HDFGRTR2_EL2().nMDSTEPOP_EL1 == '0') then AArch64_SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && MDCR_EL2().[TDE,TDA] != '00' then AArch64_SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && MDCR_EL3().EnSTEPOP == '0' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; elsif HaveEL(EL3) && MDCR_EL3().TDA == '1' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; else X{64}(t) = MDSTEPOP_EL1(); end; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3().EnSTEPOP == '0' then Undefined(); elsif HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3().TDA == '1' then Undefined(); elsif HaveEL(EL3) && MDCR_EL3().EnSTEPOP == '0' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; elsif HaveEL(EL3) && MDCR_EL3().TDA == '1' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; else X{64}(t) = MDSTEPOP_EL1(); end; elsif PSTATE.EL == EL3 then X{64}(t) = MDSTEPOP_EL1(); end;

MSR MDSTEPOP_EL1, <Xt>

op0	op1	CRn	CRm	op2
0b10	0b000	0b0000	0b0101	0b010

if !(IsFeatureImplemented(FEAT_STEP2) && IsFeatureImplemented(FEAT_AA64)) then Undefined(); elsif PSTATE.EL == EL0 then Undefined(); elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3().EnSTEPOP == '0' then Undefined(); elsif HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3().TDA == '1' then Undefined(); elsif EL2Enabled() && IsFeatureImplemented(FEAT_FGT2) && ((HaveEL(EL3) && SCR_EL3().FGTEn2 == '0') || HDFGWTR2_EL2().nMDSTEPOP_EL1 == '0') then AArch64_SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && MDCR_EL2().[TDE,TDA] != '00' then AArch64_SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && MDCR_EL3().EnSTEPOP == '0' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; elsif HaveEL(EL3) && MDCR_EL3().TDA == '1' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; else MDSTEPOP_EL1() = X{64}(t); end; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3().EnSTEPOP == '0' then Undefined(); elsif HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3().TDA == '1' then Undefined(); elsif HaveEL(EL3) && MDCR_EL3().EnSTEPOP == '0' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; elsif HaveEL(EL3) && MDCR_EL3().TDA == '1' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; else MDSTEPOP_EL1() = X{64}(t); end; elsif PSTATE.EL == EL3 then MDSTEPOP_EL1() = X{64}(t); end;

63	62	61	60	59	58	57	56	55	54	53	52	51	50	49	48	47	46	45	44	43	42	41	40	39	38	37	36	35	34	33	32
31	30	29	28	27	26	25	24	23	22	21	20	19	18	17	16	15	14	13	12	11	10	9	8	7	6	5	4	3	2	1	0
RES0
OPCODE