76 lines
1.9 KiB
C
76 lines
1.9 KiB
C
#include <mpu.h>
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enum MPU MPU_CURRENT;
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/*
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getMPU()
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Returns the MPU identifier of the calculator.
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Thanks to SimonLothar for this function and related informations.
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Processor version register (PVR) and product control register (PRR)
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hold information about the MPU version but are only accessible for
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SH-4-based MPUs.
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Therefore, this function uses port L control register (PLCR), whose
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bits 8 to 15 cannot be set with SH7337 where bits 8 to 11 can be set
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with SH7355.
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Additionally, the CPU core ID register (CPIDR) at 0xff000048 returns 1
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on SH7305.
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@return MPU identifier as integer value.
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*/
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enum MPU getMPU(void)
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{
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// Processor version register.
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volatile unsigned int *pvr = (unsigned int *)0xff000030;
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// Product version register.
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volatile unsigned int *prr = (unsigned int *)0xff000044;
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// Port L control register.
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volatile unsigned short *plcr = (unsigned short *)0xa4000114;
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// Saved value for PLCR.
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unsigned short saved_plcr;
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unsigned int tested_plcr;
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// Looking for SH-3-based MPUs by testing PLCR writing access.
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saved_plcr = *plcr;
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*plcr = 0xffff;
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tested_plcr = *plcr;
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*plcr = saved_plcr;
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// Checking whether we are working with an SH7337 or an SH7355.
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if(tested_plcr == 0x00ff) return MPU_SH7337;
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if(tested_plcr == 0x0fff) return MPU_SH7355;
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// Looking for SH-4-based MPUs by testing the version registers. This
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// needs to have the three upper bytes of the processor version
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// register match 0x10300b :
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if((*pvr & 0xffffff00) != 0x10300b00) return MPU_Unknown;
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// Now that we have an SH-4-based MPU, checking whether it is SH7305 or
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// SH7724.
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switch(*prr & 0xfffffff0)
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{
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case 0x00002c00:
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return MPU_SH7305;
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case 0x00002200:
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return MPU_SH7724;
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}
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// By default, the MPU is unknown.
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return MPU_Unknown;
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}
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/*
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mpu_init()
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Determines the MPU type and stores the result into MPU_CURRENT.
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*/
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void mpu_init(void)
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{
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MPU_CURRENT = getMPU();
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}
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