Table of Contents
Advertisement
Analyzing the PowerPC 604
Using the Inverse Assembler
The Raw dialect provides mnemonics and operands as specified by the
PowerPC programming enviromnent, eg the rotate left word inunediate
then and with mask instruction:
rlwinm r30 r30 16. 16. 31.
The Simplified dialect simplifies the operands for the rotate instructions:
the rlwimn bit mask is presented as the hex value of the mask generated by
the two decimal bit numbers:
rlwinm r30 r30 16. OOOOFFFF
Additionally, a number of common extensions to PowerPC assembly language
are decoded:
• Conditional traps and branches decode the condition mnemonically when
possible. For some conditions which have no conventional mnemonics (for
example, "signed less
than
or unsigned greater than"), the condition field
is displayed in binary.
• The L bit is omitted as a compare operand. Instead, compares are
decoded as "cmpw" (or "?cmpd").
• "Add inunediate" instructions with a negative immediate operand are
decoded as subtract immediate ("subi").
• "Subtract from" instructions subf and subfc are decoded as subtract
instructions sub and subc with the operands exchanged so that "sub r3 r4
r5" is mnemonically interpreted as "r3
=
r4 - r5.''
• ori rO rO 0000 is decoded as "nop".
• add immediate and add immediate shifted instructions, addi and addis,
with a null source register are decoded as load immediate and load
immediate shifted, li and lis.
• or instructions with identical source registers are decoded as move
register, mr.
• nor instructions with identical source registers are decoded as not
register, not.
• xor and eqv instructions with identical source and destination registers are
decoded as clear and set, clr and set, respectively.
• The cror, crnor, crxor, and creqv instructions map analogously to crmv,
crnot, crclr, and crset.
• When the mtcrf instruction field mask specifies the entire er, it is decoded
asmtcr.
E2465A PowerPC 604 PGA Preprocessor
2-21
Advertisement
Table of Contents
