dsp56000 Freescale Semiconductor, Inc, dsp56000 Datasheet - Page 565

• Manufacturer Part Number: dsp56000
• Description: 24-bit Digital Signal Processor Family Manual
• Manufacturer: Freescale Semiconductor, Inc

will require
and will execute in
Example 18: RTI Instruction
Problem: Calculate the number of 24-bit instruction program words and the number of
oscillator clock cycles required for the instruction
where
Solution: To determine the number of instruction program words and the number of
oscillator clock cycles required for the given instruction, the user should perform the fol-
lowing operations:
1. Look up the number of instruction program words and the number of oscillator clock
According to Table A-6, the RTI instruction will require one instruction program word and
will execute in (4+rx) oscillator clock cycles. The term “rx’’ represents the number of addi-
tional (if any) oscillator clock cycles required for an RTI or RTS instruction.
2. Evaluate the “rx’’ term using Table A-12.
According to Table A-12, the RTI instruction will require rx=(2
clock cycles. The term “ap’’ represents the number of additional (if any) oscillator clock
cycles that are required to access a P memory operand. Note that the term “(2 ap)” rep-
resents the two program memory instruction fetches executed at the end of an RTI or
RTS instruction to refill the instruction pipeline.
MOTOROLA
cycles required for the opcode-operand portion of the instruction in Table A-6.
Operating Mode Register (OMR)
Bus Control Register (BCR)
Return Address (on the stack)
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INSTRUCTION SET DETAILS
= (1+ea)
= (1+0)
= 1
= (4+jx)
= (4+ea+(2
= (4+ea+(2
= (4+2+(2
=
JLC (R2+N2)
INSTRUCTION TIMING
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14
RTI
4)) oscillator clock cycles.
ap))
wp))
instruction program word
= 02 (normal expanded memory map),
= $0012, and,
= $0100 (internal P memory).
ap) additional oscillator
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