AN2491 Freescale Semiconductor / Motorola, AN2491 Datasheet - Page 9

• Manufacturer Part Number: AN2491
• Description: Simplified Mnemonics for PowerPC Instructions
• Manufacturer: Freescale Semiconductor / Motorola

To provide simplified mnemonics for every possible combination of BO and BI (that is, including bits that
identified the CR field) would require 2
useful. The abbreviated set in Section 4.5, “Simplified Mnemonics that Incorporate the BO Operand,”
covers useful cases. Unusual cases can be coded using a standard branch conditional syntax.
4.4.1.2 The crS Operand
The crS symbols are shown in Table 9. Note that either the symbol or the operand value can be used in the
syntax used with the simplified mnemonic.
MOTOROLA
CRn[0]
CRn[1]
CRn[2]
CRn[3] 4 * cr0 + so/un (or so/un)
CRn
Bit
4 * cr0 + eq (or eq)
4 * cr0 + gt (or gt)
4 * cr0 + lt (or lt)
Bit Expression
4 * cr1 + so/un
4 * cr2 + so/un
4 * cr3 + so/un
4 * cr4 + so/un
4 * cr5 + so/un
4 * cr6 + so/un
4 * cr7 + so/un
4 * cr1 + eq
4 * cr2 + eq
4 * cr4 + eq
4 * cr5 + eq
4 * cr6 + eq
4 * cr7 + eq
4 * cr1 + gt
4 * cr2 + gt
4 * cr4 + gt
4 * cr5 + gt
4 * cr6 + gt
4 * cr7 + gt
4 * cr3+ eq
4 * cr3+ gt
4 * cr1 + lt
4 * cr2 + lt
4 * cr4 + lt
4 * cr5 + lt
4 * cr6 + lt
4 * cr7 + lt
4 * cr3+ lt
Table 8. BI Operand Settings for CR Fields for Branch Comparisons
cr0 (default, can be eliminated from syntax)
Simplified Mnemonics for PowerPC™ Instructions
Freescale Semiconductor, Inc.
For More Information On This Product,
Table 9. CR Field Identification Symbols
Operand)
AIM (BI
Symbol
12
16
20
24
28
13
17
21
25
29
10
14
18
22
26
30
15
19
23
27
31
11
0
4
8
1
5
9
2
6
3
7
cr1
CR Bits
Go to: www.freescale.com
10
= 1024 mnemonics, most of which would be only marginally
Book E 0–2 3–4
32
36
40
44
48
52
56
60
33
37
41
45
49
53
57
61
34
38
42
46
50
54
58
62
35
39
43
47
51
55
59
63
000
001
010
100
101
000
001
010
100
101
000
001
010
100
101
000
001
010
100
101
011
110
111
011
110
111
011
110
111
011
110
111
BI
00 Less than or floating-point less than (LT, FL).
01 Greater than or floating-point greater than (GT,
10 Equal or floating-point equal (EQ, FE).
11 Summary overflow or floating-point unordered
BI[0–2]
Branch Instruction Simplified Mnemonics
000
001
For integer compare instructions:
rA < SIMM or rB (signed comparison) or rA <
UIMM or rB (unsigned comparison).
For floating-point compare instructions: frA < frB.
FG).
For integer compare instructions:
rA > SIMM or rB (signed comparison) or rA >
UIMM or rB (unsigned comparison).
For floating-point compare instructions: frA > frB.
For integer compare instructions: rA = SIMM,
UIMM, or rB.
For floating-point compare instructions: frA = frB.
(SO, FU).
For integer compare instructions, this is a copy of
XER[SO] at instruction completion.
For floating-point compare instructions, one or
both of frA and frB is a NaN.
CR Bits
32–35
36–39
Description
9