21.4.2 x86

set struct-convention mode

Set the convention used by the inferior to return structs and unions from functions to mode. Possible values of mode are "pcc", "reg", and "default" (the default). "default" or "pcc" means that structs are returned on the stack, while "reg" means that a struct or a union whose size is 1, 2, 4, or 8 bytes will be returned in a register.

show struct-convention

Show the current setting of the convention to return structs from functions.

21.4.2.1 x87 registers

GDB provides access to the x87 state through the following registers:

• $st0 to st7: ST(0) to ST(7) floating-point registers
• $fctrl: control word register (FCW)
• $fstat: status word register (FSW)
• $ftag: tag word (FTW)
• $fiseg: last instruction pointer segment
• $fioff: last instruction pointer
• $foseg: last data pointer segment
• $fooff: last data pointer
• $fop: last opcode