W65C832_1 Datasheet, PDF (57/64 Pages) –

WDC
THE WESTERN DESIGN CENTER, INC.
w65C832
7.3.3.4 The assembler shall use the <, >, and A characters after the #:
character in immediate address to specify which byte or bytes will be
selected from the value of the operand. Any calculations in the operand
must be performed before the byte selection takes place. Table 7-3-2
defines the action taken by each operand by showing the effect of the
operator on an address. The column that shows a two byte immediate
value show the bytes in the order in which they appear in memory. The
coding of the operand is for an assembler which uses 32 bit address
calculations, showing the way that the address should be reduced to a 24
bit value.
Table 7-3-2 Byte Selection Operator
Operand One Byte Result Two Byte Result Four Byte Result
#$01020304
04
#<$01020304
04
#>$01020304
03
1"$01020304
02
03 04
03 04
02 03
01 01
01 02 03 04
7.3.3.5 In any location in an operand where an address, or expression
resulting in an address, can be coded, the assembler shall recognize the
prefix characters <, I, and >, which force one byte (direct page), two
byte (absolute) or three byte (long absolute) addressing. In cases
where the addressing modes is not forced, the assembler shall assume
that the address is two bytes unless the assembler is able to determine
the type of addressing required by context, in which case that
addressing mode will be used. Addresses shall be truncated without
error in an addressing mode is forced which does not require the entire
value of the address. For example,
LDA $0203
LDA \$010203­
are completely equivalent. If the addressing mode is not forced, and
the type of addressing cannot be determined from context,t he assembler
shall assume that a two byte address is to be used. If an instruction
does not have a short addressing mode (as in LDA< which ahs no direct
page indexed by Y) and a short address is used in the operand, the
assembler shall automatically extend the address by padding the most
significant bytes with zeroes in order to extend the address to the
length needed. As with immediate address, any expression evaluation
shall take place before the address is selected; thus, the address
selection character is only used once, before the address of expression.
7.3.3.6 The! (exclamation point) character should be supported as an
alternative to the I (vertical bar).
7.3.3.7 A long indirect address is indicated in the operand field of an
instruction field of an instruction by surrounding the direct page
address where the indirect address is found by square brackets; direct
page addresses which contain sixteen-bit addresses are indicated by
being surrounded by parentheses.
7.3.3.8 The operands of a block move instruction are specified as
source bank, destination bank-the opposite order of tzz object bytes
generated.
7.3.4 Comment Field--The comment field may start no sooner than one space
after the operation code field or operand field depending on instruction
~
type.
/'
MARCH 1990
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