@c Copyright (C) 1991-2024 Free Software Foundation, Inc.
@c This is part of the GAS manual.
@c For copying conditions, see the file as.texinfo.
@page
@node SH-Dependent
@chapter Renesas / SuperH SH Dependent Features
@cindex SH support
@menu
* SH Options:: Options
* SH Syntax:: Syntax
* SH Floating Point:: Floating Point
* SH Directives:: SH Machine Directives
* SH Opcodes:: Opcodes
@end menu
@node SH Options
@section Options
@cindex SH options
@cindex options, SH
@code{@value{AS}} has following command-line options for the Renesas
(formerly Hitachi) / SuperH SH family.
@item --renesas
Disable optimization with section symbol for compatibility with
Renesas assembler.
@item --allow-reg-prefix
Allow '$' as a register name prefix.
@kindex --fdpic
@item --fdpic
Generate an FDPIC object file.
@item --isa=sh4 | sh4a
Specify the sh4 or sh4a instruction set.
@item --isa=dsp
Enable sh-dsp insns, and disable sh3e / sh4 insns.
@item --isa=fp
Enable sh2e, sh3e, sh4, and sh4a insn sets.
@item --isa=all
Enable sh1, sh2, sh2e, sh3, sh3e, sh4, sh4a, and sh-dsp insn sets.
@item -h-tick-hex
Support H'00 style hex constants in addition to 0x00 style.
@end table
@node SH Syntax
@section Syntax
@menu
* SH-Chars:: Special Characters
* SH-Regs:: Register Names
* SH-Addressing:: Addressing Modes
@end menu
@node SH-Chars
@subsection Special Characters
@cindex line comment character, SH
@cindex SH line comment character
@samp{!} is the line comment character.
@cindex line separator, SH
@cindex statement separator, SH
@cindex SH line separator
You can use @samp{;} instead of a newline to separate statements.
If a @samp{#} appears as the first character of a line then the whole
line is treated as a comment, but in this case the line could also be
a logical line number directive (@pxref{Comments}) or a preprocessor
control command (@pxref{Preprocessing}).
@cindex symbol names, @samp{$} in
@cindex @code{$} in symbol names
Since @samp{$} has no special meaning, you may use it in symbol names.
@node SH-Regs
@subsection Register Names
@cindex SH registers
@cindex registers, SH
You can use the predefined symbols @samp{r0}, @samp{r1}, @samp{r2},
@samp{r3}, @samp{r4}, @samp{r5}, @samp{r6}, @samp{r7}, @samp{r8},
@samp{r9}, @samp{r10}, @samp{r11}, @samp{r12}, @samp{r13}, @samp{r14},
and @samp{r15} to refer to the SH registers.
@item mach
@itemx macl
high and low multiply accumulator registers
@item sr
status register
@item gbr
global base register
@item vbr
vector base register (for interrupt vectors)
@end table
@node SH-Addressing
@subsection Addressing Modes
@cindex addressing modes, SH
@cindex SH addressing modes
@code{@value{AS}} understands the following addressing modes for the SH.
@code{R@var{n}} in the following refers to any of the numbered
registers, but @emph{not} the control registers.
@table @code
@item R@var{n}
Register direct
@item @@R@var{n}
Register indirect
@item @@-R@var{n}
Register indirect with pre-decrement
@item @@R@var{n}+
Register indirect with post-increment
@item @@(@var{disp}, R@var{n})
Register indirect with displacement
@item @@(R0, R@var{n})
Register indexed
@item @@(@var{disp}, GBR)
@code{GBR} offset
@item @@(R0, GBR)
GBR indexed
@item @var{addr}
@itemx @@(@var{disp}, PC)
PC relative address (for branch or for addressing memory). The
@code{@value{AS}} implementation allows you to use the simpler form
@var{addr} anywhere a PC relative address is called for; the alternate
form is supported for compatibility with other assemblers.
@item #@var{imm}
Immediate data
@end table
@node SH Floating Point
@section Floating Point
@cindex floating point, SH (@sc{ieee})
@cindex SH floating point (@sc{ieee})
SH2E, SH3E and SH4 groups have on-chip floating-point unit (FPU). Other
SH groups can use @code{.float} directive to generate @sc{ieee}
floating-point numbers.
SH2E and SH3E support single-precision floating point calculations as
well as entirely PCAPI compatible emulation of double-precision
floating point calculations. SH2E and SH3E instructions are a subset of
the floating point calculations conforming to the IEEE754 standard.
In addition to single-precision and double-precision floating-point
operation capability, the on-chip FPU of SH4 has a 128-bit graphic
engine that enables 32-bit floating-point data to be processed 128
bits at a time. It also supports 4 * 4 array operations and inner
product operations. Also, a superscalar architecture is employed that
enables simultaneous execution of two instructions (including FPU
instructions), providing performance of up to twice that of
conventional architectures at the same frequency.
@node SH Directives
@section SH Machine Directives
@cindex SH machine directives
@cindex machine directives, SH
@cindex @code{uaword} directive, SH
@cindex @code{ualong} directive, SH
@cindex @code{uaquad} directive, SH
@table @code
@item uaword
@itemx ualong
@itemx uaquad
@code{@value{AS}} will issue a warning when a misaligned @code{.word},
@code{.long}, or @code{.quad} directive is used. You may use
@code{.uaword}, @code{.ualong}, or @code{.uaquad} to indicate that the
value is intentionally misaligned.
@end table
@node SH Opcodes
@section Opcodes
@cindex SH opcode summary
@cindex opcode summary, SH
@cindex mnemonics, SH
@cindex instruction summary, SH
For detailed information on the SH machine instruction set, see
@cite{SH-Microcomputer User's Manual} (Renesas) or
@cite{SH-4 32-bit CPU Core Architecture} (SuperH) and
@cite{SuperH (SH) 64-Bit RISC Series} (SuperH).
@code{@value{AS}} implements all the standard SH opcodes. No additional
pseudo-instructions are needed on this family. Note, however, that
because @code{@value{AS}} supports a simpler form of PC-relative
addressing, you may simply write (for example)
@example
mov.l bar,r0
@end example
@noindent
where other assemblers might require an explicit displacement to
@code{bar} from the program counter:
@example
mov.l @@(@var{disp}, PC)
@end example
@ifset SMALL
@c this table, due to the multi-col faking and hardcoded order, looks silly
@c except in smallbook. See comments below "@set SMALL" near top of this file.
