From 6500c59d704ed2bb26d44b2a0ac7151d35287fdb Mon Sep 17 00:00:00 2001
From: Graham Sanderson <graham.sanderson@raspberrypi.com>
Date: Wed, 11 Sep 2024 18:33:33 -0500
Subject: [PATCH] Add busy_wait_at_leasy_cycles to host (#1925)

---
 src/host/pico_platform/include/pico/platform.h |  4 ++++
 src/host/pico_platform/platform_base.c         | 10 ++++++++--
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/src/host/pico_platform/include/pico/platform.h b/src/host/pico_platform/include/pico/platform.h
index 6d04065a..ab7c031f 100644
--- a/src/host/pico_platform/include/pico/platform.h
+++ b/src/host/pico_platform/include/pico/platform.h
@@ -148,7 +148,11 @@ uint get_core_num();
 
 static inline uint __get_current_exception(void) {
     return 0;
+
 }
+
+void busy_wait_at_least_cycles(uint32_t minimum_cycles);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/host/pico_platform/platform_base.c b/src/host/pico_platform/platform_base.c
index 25acbf1d..f7d2c95f 100644
--- a/src/host/pico_platform/platform_base.c
+++ b/src/host/pico_platform/platform_base.c
@@ -7,9 +7,9 @@
 #include <stdio.h>
 
 #include "pico.h"
+#include "hardware/timer.h"
 
 PICO_WEAK_FUNCTION_DEF(tight_loop_contents)
-
 void PICO_WEAK_FUNCTION_IMPL_NAME(tight_loop_contents)() {
 
 }
@@ -45,4 +45,10 @@ void __breakpoint() {
     #else
         __builtin_trap();
     #endif
-}
\ No newline at end of file
+}
+
+PICO_WEAK_FUNCTION_DEF(busy_wait_at_least_cycles)
+void PICO_WEAK_FUNCTION_IMPL_NAME(busy_wait_at_least_cycles)(uint32_t cycles) {
+    // fairly arbitrary; we'll use 125Mhz as a reference
+    busy_wait_us((cycles + 124)/125);
+}