Initial Release

src/host/pico_divider/CMakeLists.txt

@@ -0,0 +1,9 @@
+add_library(pico_divider INTERFACE)
+
+target_sources(pico_divider INTERFACE
+        ${CMAKE_CURRENT_LIST_DIR}/divider.c)
+
+target_link_libraries(pico_divider INTERFACE pico_divider_headers)
+
+macro(pico_set_divider_implementation TARGET IMPL)
+endmacro()

src/host/pico_divider/divider.c

@@ -0,0 +1,114 @@
+/*
+ * Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include "pico/divider.h"
+
+// These functions save/restore divider state, so are safe to call from interrupts
+int32_t div_s32s32(int32_t a, int32_t b) {
+    return hw_divider_s32_quotient(a, b);
+}
+
+divmod_result_t divmod_s32s32(int32_t a, int32_t b) {
+    return hw_divider_divmod_s32(a, b);
+}
+
+uint32_t div_u32u32(uint32_t a, uint32_t b) {
+    return hw_divider_u32_quotient(a, b);
+}
+
+divmod_result_t divmod_u32u32(uint32_t a, uint32_t b) {
+    return hw_divider_divmod_u32(a, b);
+}
+
+static inline int __sign_of_64(int32_t v) {
+    return v > 0 ? 1 : (v < 0 ? -1 : 0);
+}
+
+typedef struct {
+    uint64_t quotient;
+    uint64_t remainder;
+} qr_u64;
+
+typedef struct {
+    int64_t quotient;
+    int64_t remainder;
+} qr_s64;
+
+// divides unsigned values a by b... (a/b) returned in low 32 bits, (a%b) in high 32 bits... results undefined for b==0
+static inline qr_u64 udiv64(uint64_t a, uint64_t b) {
+    qr_u64 rc;
+    if (!b) {
+        rc.quotient = (uint64_t)-1; // todo check this
+        rc.remainder = a;
+    } else {
+        rc.quotient = a/b;
+        rc.remainder = a%b;
+    }
+    return rc;
+}
+
+// divides signed values a by b... (a/b) returned in low 32 bits, (a%b) in high 32 bits... results undefined for b==0
+static inline qr_s64 div64(int64_t a, int64_t b) {
+    qr_s64 rc;
+    if (!b) {
+        rc.quotient = (uint64_t)(-__sign_of_64(a));
+        rc.remainder = a;
+    } else {
+        rc.quotient = a/b;
+        rc.remainder = a%b;
+    }
+    return rc;
+}
+
+int64_t div_s64s64(int64_t a, int64_t b) {
+    qr_s64 qr = div64(a, b);
+    return qr.quotient;
+}
+
+int64_t divmod_s64s64_rem(int64_t a, int64_t b, int64_t *rem) {
+    qr_s64 qr = div64(a, b);
+    *rem = qr.remainder;
+    return qr.quotient;
+}
+
+int64_t divmod_s64s64(int64_t a, int64_t b) {
+    qr_s64 qr = div64(a, b);
+    return qr.quotient;
+}
+
+uint64_t div_u64u64(uint64_t a, uint64_t b) {
+    qr_u64 qr = udiv64(a, b);
+    return qr.quotient;
+}
+
+uint64_t divmod_u64u64_rem(uint64_t a, uint64_t b, uint64_t *rem) {
+    qr_u64 qr = udiv64(a, b);
+    *rem = qr.remainder;
+    return qr.quotient;
+}
+
+uint64_t divmod_u64u64(uint64_t a, uint64_t b) {
+    qr_u64 qr = udiv64(a, b);
+    return qr.quotient;
+}
+
+// these functions are slightly faster, but unsafe the divider state, so are not generally safe to be called from interrupts
+
+int32_t div_s32s32_unsafe(int32_t a, int32_t b) { return div_s32s32(a,b); }
+int32_t divmod_s32s32_rem_unsafe(int32_t a, int32_t b, int32_t *rem) { return divmod_s32s32_rem(a, b, rem); }
+int64_t divmod_s32s32_unsafe(int32_t a, int32_t b) { return divmod_s32s32(a, b); }
+
+uint32_t div_u32u32_unsafe(uint32_t a, uint32_t b) { return div_u32u32(a, b); }
+uint32_t divmod_u32u32_rem_unsafe(uint32_t a, uint32_t b, uint32_t *rem) { return divmod_u32u32_rem(a, b, rem); }
+uint64_t divmod_u32u32_unsafe(uint32_t a, uint32_t b) { return divmod_u32u32(a, b); }
+
+int64_t div_s64s64_unsafe(int64_t a, int64_t b) { return div_s64s64(a, b); }
+int64_t divmod_s64s64_rem_unsafe(int64_t a, int64_t b, int64_t *rem) { return divmod_s64s64_rem(a, b, rem); }
+int64_t divmod_s64s64_unsafe(int64_t a, int64_t b) { return divmod_s64s64(a, b); }
+
+uint64_t div_u64u64_unsafe(uint64_t a, uint64_t b) { return div_u64u64(a, b); }
+uint64_t divmod_u64u64_rem_unsafe(uint64_t a, uint64_t b, uint64_t *rem) { return divmod_u64u64_rem(a, b, rem); }
+uint64_t divmod_u64u64_unsafe(uint64_t a, uint64_t b) { return divmod_u64u64(a, b); }