Add NVIC struct. Fixes #947 (#1199)

src/rp2040/hardware_structs/include/hardware/structs/nvic.h

diff --git a/src/rp2040/hardware_structs/include/hardware/structs/nvic.h b/src/rp2040/hardware_structs/include/hardware/structs/nvic.h
new file mode 100644
index 0000000..47bc307
--- /dev/null
+++ b/src/rp2040/hardware_structs/include/hardware/structs/nvic.h
@@ -0,0 +1,65 @@
+// THIS HEADER FILE IS AUTOMATICALLY GENERATED -- DO NOT EDIT
+
+/*
+ * Copyright (c) 2021 Raspberry Pi (Trading) Ltd.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef _HARDWARE_STRUCTS_NVIC_H
+#define _HARDWARE_STRUCTS_NVIC_H
+
+#include "hardware/address_mapped.h"
+#include "hardware/regs/m0plus.h"
+
+// Reference to datasheet: https://datasheets.raspberrypi.com/rp2040/rp2040-datasheet.pdf#tab-registerlist_m0plus
+//
+// The _REG_ macro is intended to help make the register navigable in your IDE (for example, using the "Go to Definition" feature)
+// _REG_(x) will link to the corresponding register in hardware/regs/m0plus.h.
+//
+// Bit-field descriptions are of the form:
+// BITMASK [BITRANGE]: FIELDNAME (RESETVALUE): DESCRIPTION
+
+typedef struct {
+    _REG_(M0PLUS_NVIC_ISER_OFFSET) // M0PLUS_NVIC_ISER
+    // Use the Interrupt Set-Enable Register to enable interrupts and determine which interrupts are currently enabled
+    // 0xffffffff [31:0]  : SETENA (0): Interrupt set-enable bits
+    io_rw_32 iser;
+
+    uint32_t _pad0[31];
+
+    _REG_(M0PLUS_NVIC_ICER_OFFSET) // M0PLUS_NVIC_ICER
+    // Use the Interrupt Clear-Enable Registers to disable interrupts and determine which interrupts are currently enabled
+    // 0xffffffff [31:0]  : CLRENA (0): Interrupt clear-enable bits
+    io_rw_32 icer;
+
+    uint32_t _pad1[31];
+
+    _REG_(M0PLUS_NVIC_ISPR_OFFSET) // M0PLUS_NVIC_ISPR
+    // The NVIC_ISPR forces interrupts into the pending state, and shows which interrupts are pending
+    // 0xffffffff [31:0]  : SETPEND (0): Interrupt set-pending bits
+    io_rw_32 ispr;
+
+    uint32_t _pad2[31];
+
+    _REG_(M0PLUS_NVIC_ICPR_OFFSET) // M0PLUS_NVIC_ICPR
+    // Use the Interrupt Clear-Pending Register to clear pending interrupts and determine which interrupts are currently pending
+    // 0xffffffff [31:0]  : CLRPEND (0): Interrupt clear-pending bits
+    io_rw_32 icpr;
+
+    uint32_t _pad3[95];
+
+    _REG_(M0PLUS_NVIC_IPR0_OFFSET) // M0PLUS_NVIC_IPR0
+    // (Description copied from array index 0 register M0PLUS_NVIC_IPR0 applies similarly to other array indexes)
+    //
+    // Use the Interrupt Priority Registers to assign a priority from 0 to 3 to each of the available interrupts
+    // 0xc0000000 [31:30] : IP_3 (0): Priority of interrupt 3
+    // 0x00c00000 [23:22] : IP_2 (0): Priority of interrupt 2
+    // 0x0000c000 [15:14] : IP_1 (0): Priority of interrupt 1
+    // 0x000000c0 [7:6]   : IP_0 (0): Priority of interrupt 0
+    io_rw_32 ipr[8];
+} nvic_hw_t;
+
+#define nvic_hw ((nvic_hw_t *)(PPB_BASE + M0PLUS_NVIC_ISER_OFFSET))
+
+#endif