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Instructions
MPYF32 RaH, RbH, RcH
ADDF32 RdH, ReH, RfH
32-bit Floating-Point Multiply with Parallel Add
Operands
RaH
floating-point destination register for MPYF32 (R0H to R7H)
RaH cannot be the same register as RdH
RbH
floating-point source register for MPYF32 (R0H to R7H)
RcH
floating-point source register for MPYF32 (R0H to R7H)
RdH
floating-point destination register for ADDF32 (R0H to R7H)
RdH cannot be the same register as RaH
ReH
floating-point source register for ADDF32 (R0H to R7H)
RfH
floating-point source register for ADDF32 (R0H to R7H)
Opcode
LSW: 1110 0111
0100 00ff
MSW: feee dddc
ccbb baaa
Description
Multiply the contents of two floating-point registers with parallel addition of two registers.
RaH = RbH * RcH
RdH = ReH + RfH
This instruction can also be written as:
MACF32 RaH, RbH, RcH, RdH, ReH, RfH
Restrictions
The destination register for the MPYF32 and the ADDF32 must be unique. That is, RaH
cannot be the same register as RdH.
Flags
This instruction modifies the following flags in the STF register:.
Flag
TF
ZI
NI
ZF
NF
LUF
LVF
Modified
No
No
No
No
No
Yes
Yes
The STF register flags are modified as follows:
•
LUF = 1 if MPYF32 or ADDF32 generates an underflow condition.
•
LVF = 1 if MPYF32 or ADDF32 generates an overflow condition.
Pipeline
Both MPYF32 and ADDF32 take 2 pipeline cycles (2p) That is:
MPYF32
RaH, RbH, RcH
; 2 pipeline cycles (2p)
|| ADDF32
RdH, ReH, RfH
; 2 pipeline cycles (2p)
NOP
; 1 cycle delay or non-conflicting instruction
; <-- MPYF32, ADDF32 complete, RaH, RdH updated
NOP
Any instruction in the delay slot must not use RaH or RdH as a destination register or as
a source operand.
SPRUEO2A – June 2007 – Revised August 2008
Instruction Set
105
Summary of Contents for TMS320C28 series
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Page 12: ...Introduction 12 SPRUEO2A June 2007 Revised August 2008 Submit Documentation Feedback ...
Page 20: ...CPU Register Set 20 SPRUEO2A June 2007 Revised August 2008 Submit Documentation Feedback ...
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