RealView® Development Suite AXD and armsd Debuggers Guide C.2.1. SDM format guide

C.2.1. SDM format guide

Types are defined based on fundamental types, or composites of types.

Types can be parameterized, with the parameters acting as type-modifiers. All parameters are optional. All parameters are named, and parameters are passed in a named list of (PARAMETER=VALUE, ...).

Types that can be user-visible have:

a user-visible name
an optional classification, a user-visible text string that assists the debug controller when organising a number of types. If a classification is specified, a name must be specified.

C++ style // comments are allowed, indicating that the rest of the line is a comment.

Two commands are defined, INCLUDE and TYPEDEF. These commands must appear at the beginning of a line, with no white space in front of them.

Except in definitions contained within an RDI register description file, such as armperip.xml, you can include other register type defintion files, using a #include structure:

INCLUDE “filename” // This is a comment.

The TYPEDEF command creates new types. It takes optional parameters of CLASS and NAME. If a type has a name, then it is user-visible. If it does not have a name, then it is visible only in other type definitions. Examples of types are NUMERIC, FLAG, ENUM, COMPOSITE, and IEEE_FLOAT. See SDM format reference for the definitive list.

For example,

TYPEDEF tZFLAG FLAG (SET="Z", UNSET="z") // This is a comment.
TYPEDEF tFIQ FLAG (SET="F", UNSET="f") // So is this.

Type definitions of ENUM and COMPOSITE types require more information than only the type parameter list:

TYPEDEF tMODE ENUM (WIDTH=5, DEFAULT=”Reserved”)
{
    "User"=0x10,
    "FIQ"=0x11,
    "IRQ"=0x12,
    "SVC"=0x13,
    "Abort"=0x17,
    "Undef"=0x1b,
    "System"=0x1f}

Duplicate definitions are allowed in enums, to account for partially decoded enums. For example, a type given a user-visible name:

TYPEDEF tARMID (NAME=”Chip ID”, CLASS=”ARM”) ENUM (WIDTH=32)
{
    “ARM720T” = 0x41807200,
    “ARM740T” = 0x41807400,
    ...
}

In the case of composites, each atom is a FIELD or a SEPARATOR. A FIELD is defined as groups of bits:

    FIELD [hi:lo] {,[hi:lo] {...}} (NAME=”<name>”,
                                    TYPE=<type>{(<params>, ...)},
                                    ACCESS=”<access>”)
    SEPARATOR (NAME=“String”)

Atoms combine as follows, optionally grouped using braces to provide grouping as appropriate:

TYPEDEF tPACKEDFLOAT(NAME="2x32bit float", CLASS="Floating Point")
COMPOSITE (WIDTH=64)
{
    FIELD [63:32] (NAME="High", TYPE=IEEE_FLOAT (WIDTH=32)),
    FIELD [31:0]  (NAME="Low",  TYPE=IEEE_FLOAT (WIDTH=32))
}

TYPEDEF tPACKEDQ15 (NAME="2xQ-15-format", CLASS="DSP")  COMPOSITE (WIDTH=32)
{
    FIELD [31:16] (NAME="High", TYPE=QFORMAT (N=1,M=15)),
    FIELD [15:0]  (NAME="Low",  TYPE=QFORMAT (N=1,M=15))
}

TYPEDEF tPSR (NAME=”PSR”, CLASS=”ARM”) COMPOSITE (WIDTH=32)
{
    GROUP (NAME=”Flag bits”)
    {
        FIELD [31] (NAME="Zero Flag",     TYPE=tZFLAG, ACCESS=”RW”),
        FIELD [30] (NAME="Negative Flag", TYPE=tNFLAG, ACCESS=”RW”),
        FIELD [29] (NAME="Carry Flag",    TYPE=tCFLAG, ACCESS=”RW”),
        FIELD [28] (NAME="Overflow Flag", TYPE=tVFLAG, ACCESS=”RW”)
    },
    FIELD [27:8] (TYPE=RESERVED (WIDTH=30), ACCESS=”0”),
    GROUP (NAME=”Mode bits”)
    {
        FIELD [7]  (NAME="Thumb bit",     TYPE=tTHUMB, ACCESS=”RW”),
        FIELD [6]  (NAME="IRQ bit",       TYPE=tIRQ,   ACCESS=”RW”),
        FIELD [5]  (NAME="FIQ bit",       TYPE=tFIQ,   ACCESS=”RW”),
        SEPARATOR (TEXTNAME=”_”)
        FIELD [4:0] (NAME="Mode",         TYPE=tMODE,  ACCESS=”RW”)
    }
}

The access parameter is interpreted as follows:

Table C.7. Interpretation of access parameter

Value	Meaning
R	Readable
W	Writable
V	Reserved (write as read)
Z	Write as zero (read undefined)
0	Always 0
1	Always 1
U	Undefined
X	Not readable, but caching any written values is permitted and useful
N	Not cacheable (otherwise treated as cacheable)

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