9.42.3.2 Register Names

The Sparc integer register file is broken down into global, outgoing, local, and incoming.

• The 8 global registers are referred to as ‘%gn’.
• The 8 outgoing registers are referred to as ‘%on’.
• The 8 local registers are referred to as ‘%ln’.
• The 8 incoming registers are referred to as ‘%in’.
• The frame pointer register ‘%i6’ can be referenced using the alias ‘%fp’.
• The stack pointer register ‘%o6’ can be referenced using the alias ‘%sp’.

Floating point registers are simply referred to as ‘%fn’. When assembling for pre-V9, only 32 floating point registers are available. For V9 and later there are 64, but there are restrictions when referencing the upper 32 registers. They can only be accessed as double or quad, and thus only even or quad numbered accesses are allowed. For example, ‘%f34’ is a legal floating point register, but ‘%f35’ is not.

Floating point registers accessed as double can also be referred using the ‘%dn’ notation, where n is even. Similarly, floating point registers accessed as quad can be referred using the ‘%qn’ notation, where n is a multiple of 4. For example, ‘%f4’ can be denoted as both ‘%d4’ and ‘%q4’. On the other hand, ‘%f2’ can be denoted as ‘%d2’ but not as ‘%q2’.

Certain V9 instructions allow access to ancillary state registers. Most simply they can be referred to as ‘%asrn’ where n can be from 16 to 31. However, there are some aliases defined to reference ASR registers defined for various UltraSPARC processors:

• The tick compare register is referred to as ‘%tick_cmpr’.
• The system tick register is referred to as ‘%stick’. An alias, ‘%sys_tick’, exists but is deprecated and should not be used by new software.
• The system tick compare register is referred to as ‘%stick_cmpr’. An alias, ‘%sys_tick_cmpr’, exists but is deprecated and should not be used by new software.
• The software interrupt register is referred to as ‘%softint’.
• The set software interrupt register is referred to as ‘%set_softint’. The mnemonic ‘%softint_set’ is provided as an alias.
• The clear software interrupt register is referred to as ‘%clear_softint’. The mnemonic ‘%softint_clear’ is provided as an alias.
• The performance instrumentation counters register is referred to as ‘%pic’.
• The performance control register is referred to as ‘%pcr’.
• The graphics status register is referred to as ‘%gsr’.
• The V9 dispatch control register is referred to as ‘%dcr’.

Various V9 branch and conditional move instructions allow specification of which set of integer condition codes to test. These are referred to as ‘%xcc’ and ‘%icc’.

Additionally, GAS supports the so-called “natural” condition codes; these are referred to as ‘%ncc’ and reference to ‘%icc’ if the word size is 32, ‘%xcc’ if the word size is 64.

In V9, there are 4 sets of floating point condition codes which are referred to as ‘%fccn’.

Several special privileged and non-privileged registers exist:

• The V9 address space identifier register is referred to as ‘%asi’.
• The V9 restorable windows register is referred to as ‘%canrestore’.
• The V9 savable windows register is referred to as ‘%cansave’.
• The V9 clean windows register is referred to as ‘%cleanwin’.
• The V9 current window pointer register is referred to as ‘%cwp’.
• The floating-point queue register is referred to as ‘%fq’.
• The V8 co-processor queue register is referred to as ‘%cq’.
• The floating point status register is referred to as ‘%fsr’.
• The other windows register is referred to as ‘%otherwin’.
• The V9 program counter register is referred to as ‘%pc’.
• The V9 next program counter register is referred to as ‘%npc’.
• The V9 processor interrupt level register is referred to as ‘%pil’.
• The V9 processor state register is referred to as ‘%pstate’.
• The trap base address register is referred to as ‘%tba’.
• The V9 tick register is referred to as ‘%tick’.
• The V9 trap level is referred to as ‘%tl’.
• The V9 trap program counter is referred to as ‘%tpc’.
• The V9 trap next program counter is referred to as ‘%tnpc’.
• The V9 trap state is referred to as ‘%tstate’.
• The V9 trap type is referred to as ‘%tt’.
• The V9 condition codes is referred to as ‘%ccr’.
• The V9 floating-point registers state is referred to as ‘%fprs’.
• The V9 version register is referred to as ‘%ver’.
• The V9 window state register is referred to as ‘%wstate’.
• The Y register is referred to as ‘%y’.
• The V8 window invalid mask register is referred to as ‘%wim’.
• The V8 processor state register is referred to as ‘%psr’.
• The V9 global register level register is referred to as ‘%gl’.

Several special register names exist for hypervisor mode code:

• The hyperprivileged processor state register is referred to as ‘%hpstate’.
• The hyperprivileged trap state register is referred to as ‘%htstate’.
• The hyperprivileged interrupt pending register is referred to as ‘%hintp’.
• The hyperprivileged trap base address register is referred to as ‘%htba’.
• The hyperprivileged implementation version register is referred to as ‘%hver’.
• The hyperprivileged system tick offset register is referred to as ‘%hstick_offset’. Note that there is no ‘%hstick’ register, the normal ‘%stick’ is used.
• The hyperprivileged system tick enable register is referred to as ‘%hstick_enable’.
• The hyperprivileged system tick compare register is referred to as ‘%hstick_cmpr’.