DSPIC30F5013 Microchip Technology Inc., DSPIC30F5013 Datasheet - Page 18

• Manufacturer Part Number: DSPIC30F5013
• Description: Dspic30f5011/5013 High-performance Digital Signal Controllers
• Manufacturer: Microchip Technology Inc.

dsPIC30F5011/5013
2.3
The dsPIC DSC devices feature a 16/16-bit signed
fractional divide operation, as well as 32/16-bit and 16/
16-bit signed and unsigned integer divide operations, in
the form of single instruction iterative divides. The fol-
lowing instructions and data sizes are supported:
1.
2.
3.
4.
5.
The 16/16 divides are similar to the 32/16 (same number
of iterations), but the dividend is either zero-extended or
sign-extended during the first iteration.
TABLE 2-1:
DS70116F-page 16
DIVF
DIV.sd
DIV.sw or
DIV.s
DIV.ud
DIV.uw or
DIV.u
DIVF - 16/16 signed fractional divide
DIV.sd - 32/16 signed divide
DIV.ud - 32/16 unsigned divide
DIV.sw - 16/16 signed divide
DIV.uw - 16/16 unsigned divide
Instruction
Divide Support
DIVIDE INSTRUCTIONS
Signed fractional divide: Wm/Wn
Signed divide: (Wm+1:Wm)/Wn
Signed divide: Wm/Wn
Unsigned divide: (Wm+1:Wm)/Wn
Unsigned divide: Wm/Wn
W0; Rem
W0; Rem
W0; Rem
W0; Rem
W0; Rem
W1
W1
The divide instructions must be executed within a
REPEAT loop. Any other form of execution (e.g., a
series of discrete divide instructions) will not function
correctly because the instruction flow depends on
RCOUNT. The divide instruction does not automati-
cally set up the RCOUNT value and it must, therefore,
be explicitly and correctly specified in the REPEAT
instruction as shown in Table 2-1 (REPEAT will execute
the target instruction {operand value+1} times). The
REPEAT loop count must be setup for 18 iterations of
the DIV/DIVF instruction. Thus, a complete divide
operation requires 19 cycles.
Function
Note:
W1
W1
W1
The divide flow is interruptible. However,
the user needs to save the context as
appropriate.
© 2006 Microchip Technology Inc.