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// The Potato Processor

// (c) Kristian Klomsten Skordal 2015 <kristian.skordal@wafflemail.net>

// Report bugs and issues on <http://opencores.org/project,potato,bugtracker>

#ifndef POTATO_H

#define POTATO_H

// This file contains various defines neccessary for using the Potato processor

// with current RISC-V compilers. It also makes sure that applications keep

// working even though the supervisor extension specification should change.

// Control and status registers:

#define CSR_SUP0        0x500

#define CSR_SUP1        0x501

#define CSR_EPC         0x502

#define CSR_BADVADDR    0x503

#define CSR_EVEC        0x508

#define CSR_CAUSE       0x509

#define CSR_STATUS      0x50a

#define CSR_HARTID      0x50b

#define CSR_TOHOST      0x51e

#define CSR_FROMHOST    0x51f

#define CSR_CYCLE       0xc00

#define CSR_CYCLEH      0xc80

#define CSR_TIME        0xc01

#define CSR_TIMEH       0xc81

#define CSR_INSTRET     0xc02

#define CSR_INSTRETH    0xc82

// Exception cause values:

#define CAUSE_INSTR_MISALIGN    0x00

#define CAUSE_INSTR_FETCH       0x01

#define CAUSE_INVALID_INSTR     0x02

#define CAUSE_SYSCALL           0x06

#define CAUSE_BREAKPOINT        0x07

#define CAUSE_LOAD_MISALIGN     0x08

#define CAUSE_STORE_MISALIGN    0x09

#define CAUSE_LOAD_ERROR        0x0a

#define CAUSE_STORE_ERROR       0x0b

#define CAUSE_FROMHOST          0x1e

#define CAUSE_IRQ_BASE          0x10

// Status register bit indices:

#define STATUS_EI       2               // Enable Interrupts

#define STATUS_PEI      3               // Previous value of Enable Interrupts

#define STATUS_IM_MASK  0x00ff0000      // Interrupt Mask

#define STATUS_PIM_MASK 0xff000000      // Previous Interrupt Mask

#define potato_enable_interrupts()      asm volatile("csrsi %[status], 1 << %[ei_bit]\n" \

                :: [status] "i" (CSR_STATUS), [ei_bit] "i" (STATUS_EI))

#define potato_disable_interrupts()     asm volatile("csrci %[status], 1 << %[ei_bit] | 1 << %[pei_bit]\n" \

                :: [status] "i" (CSR_STATUS), [ei_bit] "i" (STATUS_EI), [pei_bit] "i" (STATUS_PEI))

#define potato_write_host(data) \

        do { \

                register uint32_t temp = data; \

                asm volatile("csrw %[tohost], %[temp]\n" \

                        :: [tohost] "i" (CSR_TOHOST), [temp] "r" (temp)); \

        } while(0);

#define potato_enable_irq(n) \

        do { \

                register uint32_t temp = 0; \

                asm volatile( \

                        "li %[temp], 1 << %[shift]\n" \

                        "csrs %[status], %[temp]\n" \

                        :: [temp] "r" (temp), [shift] "i" (n + 16), [status] "i" (CSR_STATUS)); \

        } while(0)

#define potato_disable_irq(n) \

        do { \

                register uint32_t temp = 0; \

                asm volatile( \

                        "li %[temp], 1 << %[shift]\n" \

                        "csrc %[status], %[temp]\n" \

                        :: [temp] "r" (temp), [shift] "i" (n + 24), [status] "i" (CSR_STATUS)); \

        } while(0)

#define potato_get_badvaddr(n) \

        do { \

                register uint32_t __temp = 0; \

                asm volatile ( \

                        "csrr %[temp], %[badvaddr]\n" \

                        : [temp] "=r" (__temp) : [badvaddr] "i" (CSR_BADVADDR)); \

                n = __temp; \

        } while(0)

#endif