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SH7764 Datasheet, PDF (89/1752 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTM RISC Engine Family SH-4A Series | |||
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Section 2 Programming Model
(DBR), which can only be accessed in privileged mode. Some bits of the status register (such as
the RB bit) can only be accessed in privileged mode.
(4) System Registers
System registers comprise the multiply-and-accumulate registers (MACH/MACL), the procedure
register (PR), and the program counter (PC). Access to these registers does not depend on the
processing mode.
(5) Floating-Point Registers and System Registers Related to FPU
There are thirty-two floating-point registers, FR0âFR15 and XF0âXF15. FR0âFR15 and XF0â
XF15 can be assigned to either of two banks (FPR0_BANK0âFPR15_BANK0 or FPR0_BANK1â
FPR15_BANK1).
FR0âFR15 can be used as the eight registers DR0/2/4/6/8/10/12/14 (double-precision floating-
point registers, or pair registers) or the four registers FV0/4/8/12 (register vectors), while XF0â
XF15 can be used as the eight registers XD0/2/4/6/8/10/12/14 (register pairs) or register matrix
XMTRX.
System registers related to the FPU comprise the floating-point communication register (FPUL)
and the floating-point status/control register (FPSCR). These registers are used for communication
between the FPU and the CPU, and the exception handling setting.
Register values after a reset are shown in table 2.1.
Rev. 1.00 Nov. 22, 2007 Page 33 of 1692
REJ09B0360-0100
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