www.ti.com
Instructions
SUBF32 RdH, ReH, RfH
MOV32 RaH, mem32
32-bit Floating-Point Subtraction with Parallel Move
Operands
RdH
floating-point destination register (R0H to R7H) for the SUBF32 operation
RdH cannot be the same register as RaH
ReH
floating-point source register (R0H to R7H) for the SUBF32 operation
RfH
floating-point source register (R0H to R7H) for the SUBF32 operation
RaH
floating-point destination register (R0H to R7H) for the MOV32 operation
RaH cannot be the same register as RdH
mem32
pointer to 32-bit source memory location for the MOV32 operation
Opcode
LSW: 1110 0011
0010 fffe
MSW: eedd daaa
mem32
Description
Subtract the contents of two floating-point registers and move from memory to a
floating-point register.
RdH = ReH - RfH,
RaH = [mem32]
Restrictions
The destination register for the SUBF32 and the MOV32 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
Yes
Yes
Yes
Yes
Yes
Yes
The STF register flags are modified as follows:
•
LUF = 1 if SUBF32 generates an underflow condition.
•
LVF = 1 if SUBF32 generates an overflow condition.
The MOV32 Instruction will set the NF, ZF, NI and ZI flags as follows:
NF = RaH(31);
ZF = 0;
if(RaH(30:23) == 0) { ZF = 1; NF = 0; }
NI = RaH(31);
ZI = 0;
if(RaH(31:0) == 0) ZI = 1;
Pipeline
SUBF32 is a 2 pipeline-cycle instruction (2p) and MOV32 takes a single cycle. That is:
SUBF32
RdH, ReH, RfH
; 2 pipeline cycles (2p)
||
MOV32
RaH, mem32
; 1 cycle
; <-- MOV32 completes, RaH updated
NOP
; 1 cycle delay or non-conflicting instruction
; <-- SUBF32 completes, RdH updated
NOP
Any instruction in the delay slot must not use RdH as a destination register or as a
source operand.
SPRUEO2A – June 2007 – Revised August 2008
Instruction Set
125
Содержание TMS320C28 series
Страница 2: ...2 SPRUEO2A June 2007 Revised August 2008 Submit Documentation Feedback ...
Страница 12: ...Introduction 12 SPRUEO2A June 2007 Revised August 2008 Submit Documentation Feedback ...
Страница 20: ...CPU Register Set 20 SPRUEO2A June 2007 Revised August 2008 Submit Documentation Feedback ...
Страница 136: ...Instruction Set 136 SPRUEO2A June 2007 Revised August 2008 Submit Documentation Feedback ...