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Support use of all available scratch RAM

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This commit is contained in:
Jeremy Soller 2019-11-20 11:28:21 -07:00
parent 3e8cc817b7
commit 8950a783f4
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GPG Key ID: E988B49EE78A7FB1
2 changed files with 34 additions and 10 deletions
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2
src/board/system76/galp3-c/board.mk
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@ -16,7 +16,7 @@ SCRATCH_CC=\
sdcc \
-mmcs51 \
--model-small \
--code-size 1024 \
--code-size 2048 \
--Werror
# Convert from binary file to C header

42
src/board/system76/galp3-c/scratch.c
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@ -8,13 +8,25 @@ uint8_t __code scratch_rom[] = {
#include <scratch.h>
};
// Scratch RAM 1 is 1024 bytes, located at 2048 bytes
volatile uint8_t __xdata __at(0x0800) scratch_ram_1[1024];
// Scratch RAM 1, 2, 3, and 4 are 2048 bytes total, located at 0x0800 bytes
volatile uint8_t __xdata __at(0x0800) scratch_ram[2048];
volatile uint8_t __xdata __at(0x1043) SCAR1L;
volatile uint8_t __xdata __at(0x1044) SCAR1M;
volatile uint8_t __xdata __at(0x1045) SCAR1H;
volatile uint8_t __xdata __at(0x1046) SCAR2L;
volatile uint8_t __xdata __at(0x1047) SCAR2M;
volatile uint8_t __xdata __at(0x1048) SCAR2H;
volatile uint8_t __xdata __at(0x1049) SCAR3L;
volatile uint8_t __xdata __at(0x104A) SCAR3M;
volatile uint8_t __xdata __at(0x104B) SCAR3H;
volatile uint8_t __xdata __at(0x104C) SCAR4L;
volatile uint8_t __xdata __at(0x104D) SCAR4M;
volatile uint8_t __xdata __at(0x104E) SCAR4H;
// Create new segment located at 0x1000, after scratch ROM mapping
static void scratch_start(void) __naked {
__asm
@ -27,24 +39,36 @@ static void scratch_start(void) __naked {
// Enter scratch ROM
int scratch_trampoline(void) {
// Uses SCAR1 which is mapped at 0x0800 in data space and is 1024 bytes in
// size. SCAR0 cannot be used due to __pdata overwriting it.
// Uses SCAR1, 2, 3, and 4 which are mapped at 0x0800 in data space and are
// 2048 bytes in size. SCAR0 cannot be used due to __pdata overwriting it.
int i;
// Copy scratch ROM
for (i = 0; i < ARRAY_SIZE(scratch_rom) && i < ARRAY_SIZE(scratch_ram_1); i++) {
scratch_ram_1[i] = scratch_rom[i];
for (i = 0; i < ARRAY_SIZE(scratch_rom) && i < ARRAY_SIZE(scratch_ram); i++) {
scratch_ram[i] = scratch_rom[i];
}
// Fill the rest with nop
for (; i < ARRAY_SIZE(scratch_ram_1); i++) {
scratch_ram_1[i] = 0x00;
for (; i < ARRAY_SIZE(scratch_ram); i++) {
scratch_ram[i] = 0x00;
}
// Set mapping at 0x0000 and enable
// Set scratch RAM 1 mapping at 0x0000 and enable
SCAR1L = 0x00;
SCAR1M = 0x00;
SCAR1H = 0x00;
// Set scratch RAM 2 mapping at 0x0400 and enable
SCAR2L = 0x00;
SCAR2M = 0x04;
SCAR2H = 0x00;
// Set scratch RAM 3 mapping at 0x0600 and enable
SCAR3L = 0x00;
SCAR3M = 0x06;
SCAR3H = 0x00;
// Set scratch RAM 4 mapping at 0x0800 and enable
SCAR4L = 0x00;
SCAR4M = 0x08;
SCAR4H = 0x00;
// Jump to scratch reset function
__asm__("ljmp 0");