Sun Studio 12 Update 1: Debugging a Program With dbx

Using the `regs` Command

The regs command lets you print the value of all the registers.

Here is the syntax for the regs command:

regs [-f][-F]

-f includes floating point registers (single precision). -F includes floating point registers (double precision).

For more information, see regs Command.

For SPARC based systems:

dbx[13] regs -F
current thread: t@1
current frame:  [1]
g0-g3    0x00000000 0x0011d000 0x00000000 0x00000000
g4-g7    0x00000000 0x00000000 0x00000000 0x00020c38
o0-o3    0x00000003 0x00000014 0xef7562b4 0xeffff420
o4-o7    0xef752f80 0x00000003 0xeffff3d8 0x000109b8
l0-l3    0x00000014 0x0000000a 0x0000000a 0x00010a88
l4-l7    0xeffff438 0x00000001 0x00000007 0xef74df54
i0-i3    0x00000001 0xeffff4a4 0xeffff4ac 0x00020c00
i4-i7    0x00000001 0x00000000 0xeffff440 0x000108c4
y        0x00000000
psr      0x40400086
pc       0x000109c0:main+0x4    mov     0x5, %l0
npc      0x000109c4:main+0x8    st      %l0, [%fp - 0x8]
f0f1     +0.00000000000000e+00
f2f3     +0.00000000000000e+00
f4f5     +0.00000000000000e+00
f6f7     +0.00000000000000e+00
...

For x64 based systems:

(dbx) regs
current frame:  [1]
r15     0x0000000000000000
r14     0x0000000000000000
r13     0x0000000000000000
r12     0x0000000000000000
r11     0x0000000000401b58
r10     0x0000000000000000
r9      0x0000000000401c30
r8      0x0000000000416cf0
rdi     0x0000000000416cf0
rsi     0x0000000000401c18
rbp     0xfffffd7fffdff820
rbx     0xfffffd7fff3fb190
rdx     0x0000000000401b50
rcx     0x0000000000401b54
rax     0x0000000000416cf0
trapno  0x0000000000000003
err     0x0000000000000000
rip     0x0000000000401709:main+0xf9    movl $0x0000000000000000,0xfffffffffffffffc(%rbp)
cs      0x000000000000004b
eflags  0x0000000000000206
rsp     0xfffffd7fffdff7b0
ss      0x0000000000000043
fs      0x00000000000001bb
gs      0x0000000000000000
es      0x0000000000000000
ds      0x0000000000000000
fsbase  0xfffffd7fff3a2000
gsbase  0xffffffff80000000
(dbx) regs -F
current frame:  [1]
r15     0x0000000000000000
r14     0x0000000000000000
r13     0x0000000000000000
r12     0x0000000000000000
r11     0x0000000000401b58
r10     0x0000000000000000
r9      0x0000000000401c30
r8      0x0000000000416cf0
rdi     0x0000000000416cf0
rsi     0x0000000000401c18
rbp     0xfffffd7fffdff820
rbx     0xfffffd7fff3fb190
rdx     0x0000000000401b50
rcx     0x0000000000401b54
rax     0x0000000000416cf0
trapno  0x0000000000000003
err     0x0000000000000000
rip     0x0000000000401709:main+0xf9    movl     $0x0000000000000000,0xfffffffffffffffc(%rbp)
cs      0x000000000000004b
eflags  0x0000000000000206
rsp     0xfffffd7fffdff7b0
ss      0x0000000000000043
fs      0x00000000000001bb
gs      0x0000000000000000
es      0x0000000000000000
ds      0x0000000000000000
fsbase  0xfffffd7fff3a2000
gsbase  0xffffffff80000000
st0     +0.00000000000000000000e+00
st1     +0.00000000000000000000e+00
st2     +0.00000000000000000000e+00
st3     +0.00000000000000000000e+00
st4     +0.00000000000000000000e+00
st5     +0.00000000000000000000e+00
st6     +0.00000000000000000000e+00
st7     +NaN
xmm0a-xmm0d     0x00000000 0xfff80000 0x00000000 0x00000000
xmm1a-xmm1d     0x00000000 0x00000000 0x00000000 0x00000000
xmm2a-xmm2d     0x00000000 0x00000000 0x00000000 0x00000000
xmm3a-xmm3d     0x00000000 0x00000000 0x00000000 0x00000000
xmm4a-xmm4d     0x00000000 0x00000000 0x00000000 0x00000000
xmm5a-xmm5d     0x00000000 0x00000000 0x00000000 0x00000000
xmm6a-xmm6d     0x00000000 0x00000000 0x00000000 0x00000000
xmm7a-xmm7d     0x00000000 0x00000000 0x00000000 0x00000000
xmm8a-xmm8d     0x00000000 0x00000000 0x00000000 0x00000000
xmm9a-xmm9d     0x00000000 0x00000000 0x00000000 0x00000000
xmm10a-xmm10d   0x00000000 0x00000000 0x00000000 0x00000000
xmm11a-xmm11d   0x00000000 0x00000000 0x00000000 0x00000000
xmm12a-xmm12d   0x00000000 0x00000000 0x00000000 0x00000000
xmm13a-xmm13d   0x00000000 0x00000000 0x00000000 0x00000000
xmm14a-xmm14d   0x00000000 0x00000000 0x00000000 0x00000000
xmm15a-xmm15d   0x00000000 0x00000000 0x00000000 0x00000000
fcw-fsw  0x137f 0x0000
fctw-fop        0x0000 0x0000
frip     0x0000000000000000
frdp     0x0000000000000000
mxcsr    0x00001f80
mxcr_mask       0x0000ffff
(dbx)

Platform-Specific Registers

The following tables list platform-specific register names for SPARC architecture, x86 architecture, and AMD64 architecture that can be used in expressions.

SPARC Register Information

The following register information is for [Please define the SPARCsans text entity] architecture.

Register	Description
`$g0 through $g7`	Global registers
`$o0 through $o7`	“out” registers
`$l0 through $l7`	“local” registers
`$i0 through $i7`	“in” registers
`$fp`	Frame pointer, equivalent to register $i6
`$sp`	Stack pointer, equivalent to register $o6
`$y`	Y register
`$psr`	Processor state register
`$wim`	Window invalid mask register
`$tbr`	Trap base register
`$pc`	Program counter
`$npc`	Next program counter
`$f0 through $f31`	FPU “f” registers
`$fsr`	FPU status register
`$fq`	FPU queue

The $f0f1 $f2f3 ... $f30f31 pairs of floating-point registers are treated as having C “double” type (normally $fN registers are treated as C “float” type). These pairs can also be referred to as $d0 ... $d30.

The following additional registers are available on SPARC V9 and V8+ hardware:

$g0g1 through $g6g7
$o0o1 through $o6o7
$xfsr $tstate $gsr
$f32f33 $f34f35 through $f62f63 ($d32 ... $$d62)

See the SPARC Architecture Reference Manual and the SPARC Assembly Language Reference Manual for more information on SPARC registers and addressing.

x86 Register Information

The following register information is for x86 architecture.

Register	Description
`$gs`	Alternate data segment register
`$fs`	Alternate data segment register
`$es`	Alternate data segment register
`$ds`	Data segment register
`$edi`	Destination index register
`$esi`	Source index register
`$ebp`	Frame pointer
`$esp`	Stack pointer
`$ebx`	General register
`$edx`	General register
`$ecx`	General register
`$eax`	General register
`$trapno`	Exception vector number
`$err`	Error code for exception
`$eip`	Instruction pointer
`$cs`	Code segment register
`$eflags`	Flags
`$uesp`	User stack pointer
`$ss`	Stack segment register

Commonly used registers are also aliased to their machine independent names.

Register	Description
`$sp`	Stack pointer; equivalent of `$uesp`
`$pc`	Program counter; equivalent of `$eip`
`$fp`	Frame pointer; equivalent of `$ebp`

Registers for the 80386 lower halves (16 bits) are:

Register	Description
`$ax`	General register
`$cx`	General register
`$dx`	General register
`$bx`	General register
`$si`	Source index register
`$di`	Destination index register
`$ip`	Instruction pointer, lower 16 bits
`$flags`	Flags, lower 16 bits

The first four 80386 16-bit registers can be split into 8-bit parts:

Register	Description
`$al`	Lower (right) half of register `$ax`
`$ah`	Higher (left) half of register `$ax`
`$cl`	Lower (right) half of register `$cx`
`$ch`	Higher (left) half of register `$cx`
`$dl`	Lower (right) half of register `$dx`
`$dh`	Higher (left) half of register `$dx`
`$bl`	Lower (right) half of register `$bx`
`$bh`	Higher (left) half of register `$bx`

Registers for the 80387 are:

Register	Description
`$fctrl`	Control register
`$fstat`	Status register
`$ftag`	Tag register
`$fip`	Instruction pointer offset
`$fcs`	Code segment selector
`$fopoff`	Operand pointer offset
`$fopsel`	Operand pointer selector
`$st0 through $st7`	Data registers

AMD64 Register Information

The following r egister information is for AMD64 architecture:

Register	Description
`rax`	General purpose register - argument passing for function calls
`rbx`	General purpose register - callee-saved
`rcx`	General purpose register - argument passing for function calls
`rdx`	General purpose register - argument passing for function calls
`rbp`	General purpose register - stack management/frame pointer
`rsi`	General purpose register - argument passing for function calls
`rdi`	General purpose register - argument passing for function calls
`rsp`	General purpose register - stack management/stack pointer
`r8`	General purpose register - argument passing for function calls
`r9`	General purpose register - argument passing for function calls
`r10`	General purpose register - temporary
`r11`	General purpose register - temporary
`r12`	General purpose register - callee-saved
`r13`	General purpose register - callee-saved
`r14`	General purpose register - callee-saved
`r15`	General purpose register - callee-saved
`rflags`	Flags register
`rip`	Instruction pointer
`mmx0/st0`	64-bit media and floating point register
`mmx1/st1`	64-bit media and floating point register
`mmx2/st2`	64-bit media and floating point register
`mmx3/st3`	64-bit media and floating point register
`mmx4/st4`	64-bit media and floating point register
`mmx5/st5`	64-bit media and floating point register
`mmx6/st6`	64-bit media and floating point register
`mmx7/st7`	64-bit media and floating point register
`xmm0`	128-bit media register
`xmm1`	128-bit media register
`xmm2`	128-bit media register
`xmm3`	128-bit media register
`xmm4`	128-bit media register
`xmm5`	128-bit media register
`xmm6`	128-bit media register
`xmm7`	128-bit media register
`xmm8`	128-bit media register
`xmm9`	128-bit media register
`xmm10`	128-bit media register
`xmm11`	128-bit media register
`xmm12`	128-bit media register
`xmm13`	128-bit media register
`xmm14`	128-bit media register
`xmm15`	128-bit media register
`cs`	Segment register
`os`	Segment register
`es`	Segment register
`fs`	Segment register
`gs`	Segment register
`ss`	Segment register
`fcw`	`fxsave` and `fxstor` memory image control word
`fsw`	`fxsave` and `fxstor` memory image status word
`ftw`	`fxsave` and `fxstor` memory image tag word
`fop`	`fxsave` and `fxstor` memory image last x87 op code
`frip`	`fxsave` and `fxstor` memory image 64-bit offset into the code segment
`frdp`	`fxsave` and `fxstor` memory image 64-bit offset into the date segment
`mxcsr`	`fxsave` and `fxstor` memory image 128 media instruction control and status register
`mxcsr_mask`	set bits in `mxcsr_mask` indicate supported feature bits in `mxcsr`

Using the regs Command

Platform-Specific Registers

SPARC Register Information

x86 Register Information

AMD64 Register Information

Using the `regs` Command