Remove printchar, printflush, and drawflush instructions from MLOGSYS

Author: object-Object

README.md

@@ -121,20 +121,15 @@ This non-standard extension adds instructions to control the mlogv32 processor's
 
 The MLOG instructions are encoded with an I-type instruction format using the _custom-0_ opcode. The zero-extended immediate is used as a minor opcode (funct12) for implementation reasons.
 
-The MLOGSYS instruction is used for simple system controls, including `printchar`, `printflush`, `drawflush`, and icache initialization.
+The MLOGSYS instruction is used for simple system controls, currently only including icache initialization.
 
 The `mlogsys.icache` instruction uses register _rs1_ as the number of bytes to decode. This can be generated by using a linker script to find the end address of the `.text` section and load it using `li`. The actual number of bytes decoded will be the smallest of _rs1_, the size of the icache, and the size of ROM.
 
-FIXME: `printflush` and `drawflush` are broken with subframe :(
+| funct12 | rs1    | name                  |
+| ------- | ------ | --------------------- |
+| 0       | length | Initialize ROM icache |
 
-| funct12 | rs1     | name                  |
-| ------- | ------- | --------------------- |
-| 0       | length  | Initialize ROM icache |
-| 1       | char    | `printchar`           |
-| 2       | `00000` | `printflush`          |
-| 3       | `00000` | `drawflush`           |
-
-The MLOGDRAW instruction is used for drawing graphics using the Mlog `draw` instruction. Arguments are passed to this instruction using registers _rs1_, a1, a2, a3, a4, and a5 as necessary.
+The MLOGDRAW instruction is used for drawing graphics using the Mlog `draw` instruction. Arguments are passed to this instruction using registers _rs1_, a1, a2, a3, a4, and a5 as necessary. Due to subframe constraints, `drawflush` is executed after every `draw` call.
 
 | funct12 | rs1     | a1    | a2    | a3     | a4       | a5       | name             |
 | ------- | ------- | ----- | ----- | ------ | -------- | -------- | ---------------- |

asm/print.s

@@ -3,17 +3,21 @@ _start:
     la s0, msg
     li s1, 0
     la s2, msg_len
+
+    # UART0
+    li a0, 0xf0000010
+
+    li t0, 0b111
+    sb t0, 8(a0) # FCR
 
 loop:
     lbu t0, 0(s0)
-    .insn i CUSTOM_0, 0, zero, t0, 1 # printchar
+    sb t0, 0(a0) # THR
 
     addi s0, s0, 1
     addi s1, s1, 1
     blt s1, s2, loop
 
-    .insn i CUSTOM_0, 0, zero, zero, 2 # printflush
-
     # halt
     li t0, 0xfffffff0
     sw zero, 0(t0)

coremark/mlogv32/xmlogsys.h

@@ -1,7 +1,3 @@
-#define MLOGSYS_printchar(c) asm volatile (".insn i CUSTOM_0, 0, zero, %0, 1" : : "r" (c) )
-#define MLOGSYS_printflush() asm volatile (".insn i CUSTOM_0, 0, zero, zero, 2" : : )
-#define MLOGSYS_drawflush() asm volatile (".insn i CUSTOM_0, 0, zero, zero, 3" : : )
-
 #define _declare_MLOGDRAW_0(NAME) \
 void MLOGDRAW_ ## NAME ()
 

rust/examples/demo/src/main.rs

@@ -38,8 +38,6 @@ fn main() -> ! {
     draw_rect(28, 12, 2, 12);
     draw_rect(32, 12, 8, 2);
 
-    draw_flush();
-
     let cycle1 = cycle::read();
     let instret1 = instret::read();
     let time1 = time::read();
@@ -51,7 +49,5 @@ fn main() -> ! {
     print_str("\ntime 1: ");
     print_str(buf.format(time1));
 
-    print_flush();
-
     halt()
 }

rust/examples/sortKB/src/main.rs

@@ -43,7 +43,6 @@ fn main() -> ! {
         {
             printer.print_char(uart1.uart_mut().read_byte() as char);
             printer.flush();
-            draw_flush();
         }
 
         spin_loop();
@@ -81,7 +80,6 @@ impl DisplayPrinter {
         draw_reset();
         draw_clear(0, 0, 0);
         draw_col(0xffffffff);
-        draw_flush();
     }
 
     pub fn print_str(&mut self, s: &str) {

rust/examples/timer/src/main.rs

@@ -5,7 +5,7 @@ use core::{cell::RefCell, hint};
 
 use critical_section::Mutex;
 use itoa::Buffer;
-use mlogv32::io::{print_flush, print_str};
+use mlogv32::io::print_str;
 use riscv::{
     interrupt::{self, Interrupt},
     register::mie,
@@ -42,7 +42,6 @@ fn machine_timer() {
 
         let mut buf = Buffer::new();
         print_str(buf.format(mtime));
-        print_flush();
     });
 }
 

rust/mlogv32/src/graphics.rs

@@ -206,12 +206,3 @@ pub fn draw_reset() {
         );
     };
 }
-
-pub fn draw_flush() {
-    unsafe {
-        asm!(
-            ".insn i CUSTOM_0, 0, zero, zero, 3",
-            options(nomem, preserves_flags, nostack),
-        );
-    };
-}

rust/mlogv32/src/io.rs

@@ -1,4 +1,4 @@
-use core::{arch::asm, hint, slice};
+use core::{hint, slice};
 
 use embassy_hal_internal::atomic_ring_buffer::RingBuffer;
 use uart::{Data, FifoControl, LineStatus, Uart, address::MmioAddress};
@@ -11,23 +11,9 @@ pub fn print_str(msg: &str) {
     }
 }
 
-pub fn print_char(c: char) {
-    unsafe {
-        asm!(
-            ".insn i CUSTOM_0, 0, zero, {}, 1",
-            in(reg) c as u32,
-            options(nomem, preserves_flags, nostack),
-        );
-    };
-}
-
-pub fn print_flush() {
-    unsafe {
-        asm!(
-            ".insn i CUSTOM_0, 0, zero, zero, 2",
-            options(nomem, preserves_flags, nostack),
-        );
-    }
+pub fn print_char(_c: char) {
+    // FIXME: printchar instruction no longer exists, set up println impl similar to esp-println
+    // https://github.com/esp-rs/esp-hal/tree/84bb51215d261913f00239ecd0ed38fcd8296d0e/esp-println
 }
 
 // TODO: create Peripherals struct?

rust/mlogv32/src/panic_handler.rs

@@ -1,5 +1,5 @@
 use crate::halt;
-use crate::io::{print_flush, print_str};
+use crate::io::print_str;
 use core::panic::PanicInfo;
 
 #[panic_handler]
@@ -21,7 +21,5 @@ fn panic(info: &PanicInfo) -> ! {
         }
     }
 
-    print_flush();
-
     halt();
 }

rust/mlogv32/src/prelude.rs

@@ -1,3 +1 @@
-pub use crate::io::print_str;
-
-pub use crate::{halt, io::print_flush, sleep, sleep_n};
+pub use crate::{halt, io::print_str, sleep, sleep_n};