Renesas SH7641 - Manual (Page 76)

Section 2 CPU
Rev. 4.00 Sep. 14, 2005 Page 26 of 982
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The system registers are accessed by the LDS/STS instructions (the PC is software-accessible, but
is included here because its contents are saved in, and restored from, SPC in exception handling).
The system registers are:
• MACH: Multiply and accumulate high register
• MACL: Multiply and accumulate low register
• PR: Procedure register
• PC: Program counter
This section explains the usage of these registers in different modes.
Figures 2.1 and 2.2 show the register configuration in each processing mode.
The DSP mode is switched by means of the DSP bit in the status register.