From 2e6cf7b7d058234cc0fa9ff7dc70d5e1d4b26f4b Mon Sep 17 00:00:00 2001
From: logicog <git@logicog.de>
Date: Tue, 5 Aug 2025 09:29:46 +0200
Subject: [PATCH] Add functionallity to find a mark in the flash buffer for
 dynamic HTML pages

---
 rtl837x_flash.c | 85 +++++++++++++++++++++++++++++++++++++++++++++++++
 rtl837x_flash.h |  1 +
 2 files changed, 86 insertions(+)

diff --git a/rtl837x_flash.c b/rtl837x_flash.c
index 9057c81..27fac97 100644
--- a/rtl837x_flash.c
+++ b/rtl837x_flash.c
@@ -8,6 +8,8 @@
 #include "rtl837x_sfr.h"
 
 __xdata uint8_t dio_enabled;
+__xdata uint8_t markbuf[16];
+extern __xdata uint16_t mpos;
 
 #pragma codeseg BANK1
 
@@ -66,6 +68,7 @@ void flash_init(uint8_t enable_dio) __banked
 	flash_configure_mmio();
 }
 
+
 uint8_t flash_read_status(void)
 {
 	// Test Controller Busy (we might call this directly after executing a command)
@@ -263,6 +266,88 @@ void flash_read_bulk(register __xdata uint8_t *dst, __xdata uint32_t src, regist
 }
 
 
+void flash_find_mark(__xdata uint32_t src, register uint16_t len, __code uint8_t *mark) __banked
+{
+	uint16_t status;
+	do {
+		status = flash_read_status();
+	} while (status & 0x1);
+
+	// Set fast read mode
+	if (dio_enabled) {
+		SFR_FLASH_MODEB = 0x18;
+		SFR_FLASH_CMD_R = 0xbb;
+		SFR_FLASH_DUMMYCICLES = 4;
+	} else {
+		SFR_FLASH_MODEB = 0x0;
+		SFR_FLASH_CMD_R = 0xb;	// Fast read
+		SFR_FLASH_DUMMYCICLES = 8;	// Add 8 dummy clocks after read?
+	}
+
+	uint8_t i = 0;
+	uint8_t l = 0;
+	uint8_t k;
+
+	// Calculate the length
+	while (mark[i++])
+		l++;
+
+	if (l >= 12) {
+		mpos = 0xffff;
+		return;
+	}
+
+	i = 0;
+	SFR_FLASH_TCONF = 4;
+	while (len) {
+		SFR_FLASH_ADDR16 = src >> 16;
+		SFR_FLASH_ADDR8 = src >> 8;
+		SFR_FLASH_ADDR0 = src;
+		src += 4;
+
+		SFR_FLASH_EXEC_GO = 1;
+		while(SFR_FLASH_EXEC_BUSY);
+		markbuf[i++] = SFR_FLASH_DATA0;
+		if (len != 1) {
+			markbuf[i++] = SFR_FLASH_DATA8;
+			if (len != 2) {
+				markbuf[i++] = SFR_FLASH_DATA16;
+				if (len != 3) {
+					markbuf[i++] = SFR_FLASH_DATA24;
+				} else {
+					markbuf[i++] = 0;
+				}
+			} else {
+				markbuf[i++] = 0;
+			}
+		} else {
+			markbuf[i++] = 0;
+		}
+
+		len -= 4;
+		uint8_t j = 0;
+		k = (i + 13 - l) & 0xf;
+		i &= 0xf;
+		while (mark[j] && (k != ((i) & 0xf))) {
+			if (mark[j] != markbuf[k]) {
+				k = k - j + 17;
+				j = 0;
+			} else {
+				k++;
+				j++;
+			}
+			k &= 0xf;
+		}
+		if (!mark[j]) {
+			mpos =  len + l + ((4 - ( k & 0x3)) & 0x3);
+			return;
+		}
+	}
+	mpos = 0xffff;
+	return;
+}
+
+
 void flash_read_security(uint32_t addr, uint8_t len) __banked
 {
 	while (flash_read_status() & 0x1);
diff --git a/rtl837x_flash.h b/rtl837x_flash.h
index 3159458..8e44385 100644
--- a/rtl837x_flash.h
+++ b/rtl837x_flash.h
@@ -10,4 +10,5 @@ void flash_read_security(uint32_t addr, uint8_t len)__banked ;
 void flash_block_erase(uint32_t addr) __banked;
 void flash_read_bulk(register __xdata uint8_t *dst, __xdata uint32_t src, register uint16_t len) __banked;
 void flash_write_bytes(__xdata uint32_t addr, register __xdata uint8_t *ptr, register uint16_t len)__banked;
+void flash_find_mark(__xdata uint32_t src, register uint16_t len, __code uint8_t *mark) __banked;
 #endif