ARM INSTRUCTION SET
SC32442B RISC MICROPROCESSOR
3-16
IMMEDIATE OPERAND ROTATES
The immediate operand rotate field is a 4 bit unsigned integer which specifies a shift operation on the 8 bit
immediate value. This value is zero extended to 32 bits, and then subject to a rotate right by twice the value in the
rotate field. This enables many common constants to be generated, for example all powers of 2.
WRITING TO R15
When Rd is a register other than R15, the condition code flags in the CPSR may be updated from the ALU flags
as described above.
When Rd is R15 and the S flag in the instruction is not set the result of the operation is placed in R15 and the
CPSR is unaffected.
When Rd is R15 and the S flag is set the result of the operation is placed in R15 and the SPSR corresponding to
the current mode is moved to the CPSR. This allows state changes which automatically restore both PC and
CPSR. This form of instruction should not be used in User mode.
USING R15 AS AN OPERANDY
If R15 (the PC) is used as an operand in a data processing instruction the register is used directly.
The PC value will be the address of the instruction, plus 8 or 12 bytes due to instruction prefetching. If the shift
amount is specified in the instruction, the PC will be 8 bytes ahead. If a register is used to specify the shift amount
the PC will be 12 bytes ahead.
TEQ, TST, CMP AND CMN OPCODES
NOTES
TEQ, TST, CMP and CMN do not write the result of their operation but do set flags in the CPSR. An
assembler should always set the S flag for these instructions even if this is not specified in the mnemonic.
The TEQP form of the TEQ instruction used in earlier ARM processors must not be used: the PSR transfer
operations should be used instead.
The action of TEQP in the ARM920T is to move SPSR_<mode> to the CPSR if the processor is in a privileged
mode and to do nothing if in User mode.
INSTRUCTION CYCLE TIMES
Data Processing instructions vary in the number of incremental cycles taken as follows:
Table 3-4. Incremental Cycle Times
Processing Type
Cycles
Normal data processing
1S
Data processing with register specified shift
1S + 1I
Data processing with PC written
2S + 1N
Data processing with register specified shift and PC written
2S + 1N +1I
NOTE:
S, N and I are as defined sequential (S-cycle), non-sequential (N-cycle), and internal (I-cycle) respectively.
Содержание SC32442B54
Страница 1: ...SC32442B54 USER S MANUAL Revision 1 0 ...
Страница 43: ...PRODUCT OVERVIEW SC32442B RISC MICROPROCESSOR 1 42 NOTES ...
Страница 59: ...PROGRAMMER S MODEL SC32442B RISC MICROPROCESSOR 2 16 NOTES ...
Страница 123: ...ARM INSTRUCTION SET SC32442B RISC MICROPROCESSOR 3 64 NOTES ...
Страница 167: ...THUMB INSTRUCTION SET SC32442B RISC MICROPROCESSOR 4 44 NOTES ...
Страница 187: ...MEMORY CONTROLLER SC32442B RISC MICROPROCESSOR 5 20 NOTES ...
Страница 250: ...DMA SC32442B RISC MICROPROCESSOR 8 14 NOTES ...
Страница 308: ...PWM TIMER SC32442B RISC MICROPROCESSOR 10 20 NOTES ...
Страница 330: ...UART SC32442B RISC MICROPROCESSOR 11 22 NOTES ...
Страница 417: ...SC32442B RISC MICROPROCESSOR LCD CONTROLLER 15 45 NOTES ...
Страница 427: ...ADC AND TOUCH SCREEN INTERFACE SC32442B RISC MICROPROCESSOR 16 10 NOTES ...
Страница 511: ...BUS PRIORITIES SC32442B RISC MICROPROCESSOR 24 2 NOTES ...
Страница 562: ...K5D2G13ACM D075 Revision 1 0 December 2006 7 MCP MEMORY 2Gb 256Mb x8 NAND Flash Memory A Die ...
Страница 599: ...K5D2G13ACM D075 Revision 1 0 December 2006 44 MCP MEMORY 512Mb 16Mb x32 Mobile SDRAM C Die ...