Both should have "0" for low-order bit as is correctly specified in Appendix E. This may include errors detected in the architectural registers general-purpose registers, floating-point registers, ASRs, or ASI registers and other core processor hardware. With respect to little endian memory, an LDD instruction behaves as if it is composed of two bit loads, each of which is byte swapped independently before being written into each destination register. With respect to little endian memory, an LDDA instruction behaves as if it is composed of two bit loads, each of which is byte swapped independently before being written into each destination register.
TLE may be left in an undefined states by one of those events. The correction, which applies to sections 7. TLE [66] In Chapter 5, section 5.
The entire third paragraph should be replaced with:. Floating-point operations which cause an overflow or underflow condition may also cause an "inexact" condition.
For overflow and underflow conditions, FSR. On an implementation that detects tininess after rounding, trapped underflow occurs when the result, if it was rounded to a hypothetical format having the same precision as the destination but of unbounded range, would have magnitude between zero and the smallest normalized number in the actual destination format.
In an implementation that detects tininess after rounding, Table 28 applies to a narrower range of values of the exact unrounded result u. The precise bounds depend on the rounding direction specified in FSR. RD, as follows:. Then the bounds on u for which Table 28 applies are:.
Architecturally, there are no absolute trap priorities only relative trap priorities and there is no specific limit to trap priority numbers. Trap priorities are only used by a processor to choose which exception will cause a trap at any given time; a trap priority is an ordinal number which need not be stored anywhere. Therefore, the following changes should be noted:. Caption above Table 15, p.
Text of first paragraph of section 7. The words: " That diagram should be deleted and replaced by a copy of the two Format-4 diagrams from the Tcc instruction page p. See Appendix E, "Opcode Maps", for an enumeration of reserved opcodes. Should be corrected to read: If a conforming SPARC V9 implementation encounters nonzero values in these fields, its behavior is as defined in section 6.
Should be corrected to read Although such a reference is clearly inappropriate in nonprivileged software, a case can be made for either response by an implementation and both may have been implemented. In section A.
Instruction accesses are always big-endian. Instruction accesses are always performed using big-endian byte order. Instruction fetches use an implicit ASI which depends only on the current trap level. Also see section 8. In that case, a regular load triggers an exception while a non-faulting load appears possibly with the assistance of system software to ignore the exception and loads its destination register with a value of zero.
The following should replace the erroneous Programming Note:. The text under the "Description " column in the Lookaside row should be replaced by the following text:. Corrections were incorporated into R1. These corrections also appear in all subsequent revisions. Conditions Exception s Detected in f. TEM OFM For bit SPARC programs, a stack bias of bytes must be added to both the frame pointer and the stack pointer to get to the actual data of the stack frame.
See the following figure. For bit applications, the layout of the address space is closely related to that of bit applications, though the starting address and addressing limits are radically different.
The diagram below shows the default address space provided to a 64—bit application. The regions of the address space marked as reserved might not be mapped by applications. These restrictions might be relaxed on future systems.
The actual addresses in the figure above describe a particular implementation on a particular machine, and are given for illustrative purposes only.
By default, bit programs are linked with a starting address of 0x The whole program is above 4 gigabytes, including its text, data, heap, stack, and shared libraries.
This helps ensure that bit programs are correct by making it so the program will fault in the lower 4 gigabytes of its address space, if it truncates any of its pointers. While bit programs are linked above 4 gigabytes, you can still link them below 4 gigabytes by using a linker mapfile and the -M option to the compiler or linker.
See the ld 1 linker man page for more information. Different code models are available from the compiler for different purposes to improve performance and reduce code size in bit SPARC programs.
The code model is determined by the following factors:. Shorter instruction sequences can be achieved in some instances with the smaller code models. The number of instructions needed to do static data references in absolute code is the fewest for the abs32 code model and the most for the abs64 code model, while abs44 is in the middle.
Likewise, the pic code model uses fewer instructions for static data references than the PIC code model. Consequently, the smaller code models can reduce the code size and perhaps improve the performance of programs that do not need the fuller functionality of the larger code models.
Currently, for 64—bit objects, the compiler uses the abs64 model by default. You can optimize your code by using the abs44 code model; you will use fewer instructions and still cover the bit address space that the current UltraSPARC platforms support.
Search Scope:. Document Information Preface 1.
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