Interpreting Data - HP 10312D Operating Manual

Interpreting Data
Unless followed by a lower-case letter, all numeric output from the
inverse assembler is in hexadecimal format. A lower-case "o" following
a numeric value indicates an octal representation (the ESC instruction
for example). Decimal values are indicated by a lower-case "d" (as in
the INT instruction).
Analyzing the Intel 80286
1-18
Two instructions may be displayed for a single analyzer state because
the 80286 fetches a word with two instruction bytes from program
memory. If the least significant byte of this word contains a single-byte
instruction, the next sequential instruction begins in the upper byte. In
this case, the two instructions displayed on a single line are separated
by the delete symbol (
I).
Since instructions may begin in either the
lower or upper byte, the last byte of a multiple-byte instruction may
also occur in the lower byte, with a second instruction beginning in the
upper byte. In this instance, the delete symbol is displayed in the
left-most position of the mnemonic display field. Thus, the following
defmition: Any instruction appearing to the right of the delete symbol
begins in the upper byte of the fetched word.
Examples:
PUSH DXIADC BX,DX
I
CMP AX,#53E6
JO OFLOW_CIL
(PUSH occupies the lower byte; ADC begins in the
upper byte.)
(An instruction shown on a previous line uses the
lower byte; CMP begins in the upper byte.)
(JO begins in the lower byte and uses the upper byte
as
well.)
Asterisks (*) in the inverse assembler output indicate a portion (or
portions) of an instruction was not captured by the analyzer. Missing
opcodes occur frequently and are primarily due to microprocessor
prefetch activity. Storage qualification, or the use of storage windows,
can also lead to such occurrences.