
MOTOROLA
Chapter 2. Programming Model
2-25
The integer shift instructions are listed in Table 2-13.
2.3.4.2 Floating-Point Instructions
This section describes the floating-point instructions, which include the following:
Floating-point arithmetic instructions
Floating-point multiply-add instructions
Floating-point rounding and conversion instructions
Floating-point compare instructions
Floating-point status and control register instructions
Floating-point move instructions
The EC603e microprocessor provides hardware support for all 32-bit PowerPC instructions
with the exception of floating-point instructions, which, when implemented on the EC603e
microprocessor, take a floating-point unavailable exception.
See Section 2.3.4.3, “Load and Store Instructions,” for information about floating-point
loads and stores.
The PowerPC architecture supports a floating-point system as defined in the IEEE 754
standard, but requires software support to conform with that standard. All floating-point
operations conform to the IEEE 754 standard, except if software sets the non-IEEE mode
bit (NI) in the FPSCR; the 603e is in the nondenormalized mode when the NI bit is set in
the FPSCR. If a denormalized result is produced, a default result of zero is generated. The
generated zero has the same sign as the denormalized number. The 603e performs single-
and double-precision floating-point operations compliant with the IEEE-754 floating-point
standard.
Implementation Note
—Single-precision denormalized results require two additional
processor clock cycles to round. When loading or storing a single-precision denormalized
number, the load/store unit may take up to 24 processor clock cycles to convert between the
internal double-precision format and the external single-precision format.
Table 2-13. Integer Shift Instructions
Name
Mnemonic
Operand Syntax
Shift Left Word
slw (slw.)
r
A
,r
S
,r
B
Shift Right Word
srw (srw.)
r
A
,r
S
,r
B
Shift Right Algebraic Word Immediate
srawi (srawi.)
r
A
,r
S
,
SH
Shift Right Algebraic Word
sraw (sraw.)
r
A
,r
S
,r
B