AVR Instruction Set Nomenclature: Status Register (SREG ...

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ASR - Arithmetic Shift Right Description: Shifts all bits in Rd one place to the right. Bit 7 is held constant. Bit 0 is loaded into the C flag of the SREG. This operation effectively divides a signed value by two without changing its sign. The carry flag can be used to round the result. (i) 14 Operation: b7-------------------b0 C Syntax: Operands: Program Counter: (i) ASR Rd 0 ≤ d ≤ 31 PC ← PC + 1 16-bit Opcode: 1001 010d dddd 0101 Status Register (SREG) and Boolean Formulae: I T H S V N Z C - - - ⇔ ⇔ ⇔ ⇔ ⇔ S: N ⊕ V, For signed tests. V: N ⊕ C (For N and C after the shift) N: R7 Set if MSB of the result is set; cleared otherwise. Z: R7 •R6 •R5• R4 •R3 •R2• R1• R0 Set if the result is $00; cleared otherwise. C: Rd0 Set if, before the shift, the LSB of Rd was set; cleared otherwise. R (Result) equals Rd after the operation. Example: ldi r16,$10 ; Load decimal 16 into r16 asr r16 ; r16=r16 / 2 ldi r17,$FC ; Load -4 in r17 asr r17 ; r17=r17/2 Words: 1 (2 bytes) Cycles: 1 Instruction Set
BCLR - Bit Clear in SREG Description: Clears a single flag in SREG. Operation: (i) SREG(s) ← 0 Syntax: Operands: Program Counter: (i) BCLR s 0 ≤ s ≤ 7 PC ← PC + 1 16-bit Opcode: 1001 0100 1sss 1000 Status Register (SREG) and Boolean Formulae: I T H S V N Z C ⇔ ⇔ ⇔ ⇔ ⇔ ⇔ ⇔ ⇔ I: 0 if s = 7; Unchanged otherwise. T: 0 if s = 6; Unchanged otherwise. H: 0 if s = 5; Unchanged otherwise. S: 0 if s = 4; Unchanged otherwise. V: 0 if s = 3; Unchanged otherwise. N: 0 if s = 2; Unchanged otherwise. Z: 0 if s = 1; Unchanged otherwise. C: 0 if s = 0; Unchanged otherwise. Example: bclr 0 ; Clear carry flag bclr 7 ; Disable interrupts Words: 1 (2 bytes) Cycles: 1 Instruction Set 15
Page 1 and 2: Instruction Set Nomenclature: Statu
Page 3 and 4: Conditional Branch Summary Instruct
Page 5 and 6: Instruction Set Summary (Continued)
Page 7 and 8: Instruction Set Summary (Continued)
Page 9 and 10: ADC - Add with Carry Description: A
Page 11 and 12: ADIW - Add Immediate to Word Instru
Page 13: ANDI - Logical AND with Immediate I
Page 17 and 18: BRBC - Branch if Bit in SREG is Cle
Page 19 and 20: BRCC - Branch if Carry Cleared Inst
Page 21 and 22: BREQ - Branch if Equal Instruction
Page 23 and 24: BRHC - Branch if Half Carry Flag is
Page 25 and 26: BRID - Branch if Global Interrupt i
Page 27 and 28: BRLO - Branch if Lower (Unsigned) I
Page 29 and 30: BRMI - Branch if Minus Instruction
Page 31 and 32: BRPL - Branch if Plus Instruction S
Page 33 and 34: BRTC - Branch if the T Flag is Clea
Page 35 and 36: BRVC - Branch if Overflow Cleared I
Page 37 and 38: BSET - Bit Set in SREG Description:
Page 39 and 40: CALL - Long Call to a Subroutine In
Page 41 and 42: CBR - Clear Bits in Register Instru
Page 43 and 44: CLH - Clear Half Carry Flag Descrip
Page 45 and 46: CLN - Clear Negative Flag Descripti
Page 47 and 48: CLS - Clear Signed Flag Description
Page 49 and 50: CLV - Clear Overflow Flag Descripti
Page 51 and 52: COM - One’s Complement Descriptio
Page 53 and 54: CPC - Compare with Carry Instructio
Page 55 and 56: CPSE - Compare Skip if Equal Instru
Page 57 and 58: EICALL - Extended Indirect Call to
Page 59 and 60: ELPM - Extended Load Program Memory
Page 61 and 62: ESPM - Extended Store Program Memor
Page 63 and 64: FMUL - Fractional Multiply Unsigned
Page 65 and 66:
FMULSU - Fractional Multiply Signed
Page 67 and 68:
IJMP - Indirect Jump Instruction Se
Page 69 and 70:
INC - Increment Instruction Set Des
Page 71 and 72:
LD - Load Indirect from data space
Page 73 and 74:
LD (LDD) - Load Indirect from data
Page 75 and 76:
LD (LDD) - Load Indirect From data
Page 77 and 78:
LDI - Load Immediate Description: L
Page 79 and 80:
LPM - Load Program Memory Instructi
Page 81 and 82:
LSR - Logical Shift Right Instructi
Page 83 and 84:
MOVW - Copy Register Word Instructi
Page 85 and 86:
MULS - Multiply Signed Description:
Page 87 and 88:
NEG - Two’s Complement Descriptio
Page 89 and 90:
OR - Logical OR Instruction Set Des
Page 91 and 92:
OUT - Store Register to I/O Locatio
Page 93 and 94:
PUSH - Push Register on Stack Instr
Page 95 and 96:
RET - Return from Subroutine Instru
Page 97 and 98:
RJMP - Relative Jump Instruction Se
Page 99 and 100:
ROR - Rotate Right through Carry In
Page 101 and 102:
SBC - Subtract with Carry Instructi
Page 103 and 104:
SBI - Set Bit in I/O Register Instr
Page 105 and 106:
SBIS - Skip if Bit in I/O Register
Page 107 and 108:
SBR - Set Bits in Register Instruct
Page 109 and 110:
SBRS - Skip if Bit in Register is S
Page 111 and 112:
SEH - Set Half Carry Flag Descripti
Page 113 and 114:
SEN - Set Negative Flag Description
Page 115 and 116:
SES - Set Signed Flag Description:
Page 117 and 118:
SEV - Set Overflow Flag Description
Page 119 and 120:
SLEEP Description: This instruction
Page 121 and 122:
ST - Store Indirect From Register t
Page 123 and 124:
ST (STD) - Store Indirect From Regi
Page 125 and 126:
ST (STD) - Store Indirect From Regi
Page 127 and 128:
STS - Store Direct to data space In
Page 129 and 130:
SUBI - Subtract Immediate Instructi
Page 131 and 132:
TST - Test for Zero or Minus Instru
Page 133:
Atmel Headquarters Atmel Operations
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AVR Instruction Set Nomenclature: Status Register (SREG ...

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