
64-bit Saturation
Overflow:
RES3 unchanged
RES2 unchanged
RES1 = 07FFFh
RES0 = 0FFFFh
Yes
No
Underflow:
RES3 unchanged
RES2 unchanged
RES1 = 08000h
RES0 = 00000h
Yes
No
No
Yes
Overflow:
RES3 unchanged
RES2 unchanged
RES1 = 07FFFh
RES0 = 0FFFFh
Yes
No
Yes
No
32-bit Saturation
completed
Yes
No
Yes
No
No
Yes
Yes
No
Yes
No
Underflow:
RES3 unchanged
RES2 unchanged
RES1 = 08000h
RES0 = 00000h
Overflow:
RES3 = 07FFFh
RES2 = 0FFFFh
RES1 = 0FFFFh
RES0 = 0FFFFh
Underflow:
RES3 = 08000h
RES2 = 00000h
RES1 = 00000h
RES0 = 00000h
Overflow:
RES3 = 07FFFh
RES2 = 0FFFFh
RES1 = 0FFFFh
RES0 = 0FFFFh
Underflow:
RES3 = 08000h
RES2 = 00000h
RES1 = 00000h
RES0 = 00000h
64-bit Saturation
completed
32-bit Saturation
MPYC=0 and
unshifted RES3,
bit15=1
MPYC=1 and
unshifted RES3,
bit15=0
MPYFRAC=1
Unshifted RES3,
bit 15=0 and
bit 14=1
Unshifted RES3,
bit 15=1 and
bit 14=0
MPYC=0 and
unshifted RES1,
bit15=1
MPYC=1 and
unshifted RES1,
bit15=0
MPYFRAC=1
Unshifted RES1,
bit 15=0 and
bit 14=1
Unshifted RES1,
bit 15=1 and
bit 14=0
MPY32 Operation
Table 14-6. Result Availability in Saturation Mode (MPYSAT = 1)
Result Ready in MCLK Cycles
Operation
After
(OP1 × OP2)
RES0
RES1
RES2
RES3
MPYC Bit
8/16 × 8/16
3
3
N/A
N/A
3
OP2 written
24/32 × 8/16
7
7
7
7
7
OP2 written
8/16 × 24/32
7
7
7
7
7
OP2L written
4
4
4
4
4
OP2H written
24/32 × 24/32
11
11
11
11
11
OP2L written
6
6
6
6
6
OP2H written
shows the flow for 32-bit saturation used for 16×16 bit multiplications and the flow for 64-bit
saturation used in all other cases. Primarily, the saturated results depends on the carry bit MPYC and the
MSB of the result. Secondly, if the fractional mode is enabled, it depends also on the two MSBs of the
unshift result, that is, the result that is read with fractional mode disabled.
Figure 14-4. Saturation Flow Chart
418
32-Bit Hardware Multiplier (MPY32)
SLAU272C – May 2011 – Revised November 2013
Copyright © 2011–2013, Texas Instruments Incorporated