We can optimize `bloader.c` by utilizing Magic‐1's assembly instructions - retrotruestory/M1DEV GitHub Wiki

Yes, we can optimize bloader.c by utilizing Magic-1's assembly instructions directly. Here's an example approach:

// Fast copy operation using memcopy instruction
void fast_copy(void *dst, const void *src, int count) {
    __asm__(
        "copy c,%0\n\t"    // Load count into C register
        "copy b,%1\n\t"    // Load source address into B
        "copy a,%2\n\t"    // Load destination address into A 
        "memcopy"          // Execute memcopy instruction
        : 
        : "r"(count), "r"(src), "r"(dst)
        : "a", "b", "c"
    );
}

// Optimized sector read using ldcode/stcode
void read_sector(unsigned int sector, void *buffer) {
    __asm__(
        "ld.16 a,%0\n\t"   // Load sector number
        "copy b,%1\n\t"    // Load buffer address
        "ldcode.16 a,(b)"  // Read using code space access
        :
        : "r"(sector), "r"(buffer)
        : "a", "b"
    );
}

// Fast boot image load using block operations
void load_boot_image(int slot) {
    __asm__(
        "push b\n\t"           // Save B
        "ld.16 a,%0\n\t"      // Load slot number
        "shl.16 a\n\t"        // Multiply by 2 for offset
        "lea b,image_table\n\t" // Get image table address
        "add.16 b,a\n\t"      // Add offset
        "ldcode.16 a,(b)\n\t" // Load image address
        "pop b"               // Restore B
        :
        : "r"(slot)
        : "a"
    );
}

// Optimize string operations using string instructions
void copy_string(char *dst, const char *src) {
    __asm__(
        "copy b,%0\n\t"    // Load destination
        "copy a,%1\n\t"    // Load source
        "strcopy"          // Execute string copy
        :
        : "r"(dst), "r"(src)
        : "a", "b"
    );
}

The optimizations include:

1. Using memcopy instruction for block data transfers
2. Direct use of ldcode/stcode for memory access
3. Hardware-assisted string operations
4. Efficient register usage (A, B, C registers)
5. Block operations where possible
6. Minimal memory access overhead

Note that this is a simplified example - a full implementation would need careful consideration of:

• Error handling
• Interrupt states
• Page table management
• Device access synchronization

The key is using Magic-1's specialized instructions like memcopy, ldcode, and block operations to reduce the number of individual memory accesses and take advantage of the hardware acceleration features.

Let me help you optimize the bootloader code using Magic-1's native assembly instructions. Here are all possible optimization approaches:

1. Direct Assembly Optimization

   • Replace critical C functions with assembly
   • Use block operations for memory transfers
   • Optimize register usage
   • Use specialized Magic-1 instructions

2. Hybrid C/Assembly Approach

   • Keep main logic in C
   • Create assembly routines for performance-critical sections
   • Use inline assembly in C code

3. Memory Management Optimization

   • Use direct memory addressing
   • Optimize page table access
   • Use block copy instructions

Let's implement the first approach - optimizing sector reading with assembly:

        .cseg
        .global _fast_read_sector
        
_fast_read_sector:
        enter   4               ; Setup stack frame
        
        ; Get parameters from stack
        ld.16   a,6(sp)        ; Load sector number
        ld.16   b,8(sp)        ; Load buffer address
        
        ; Save registers we'll use
        push    c
        
        ; Setup IDE parameters
        ld.8    a,0xB0         ; IDE command register
        st.8    0xFFB0(dp),a   ; Select master drive
        
        ; Transfer size is 512 bytes
        ld.16   c,512          ; Set transfer count
        
        ; Start transfer loop
.loop:
        memcopy                 ; Use hardware assisted copy
        sub.16  c,2            ; Decrement count
        br.ne   .loop          ; Continue if not done
        
        ; Restore registers
        pop     c
        
        leave                   ; Restore stack frame
        ret

        .end

To use this optimized version, modify the C code:

extern void fast_read_sector(uint16_t sector, void* buffer);

void read_sector(unsigned int sector, void *buffer) {
    #ifdef USE_OPTIMIZED
        fast_read_sector(sector, buffer);
    #else
        // ... existing code ...
    #endif
}

This optimization:

1. Uses memcopy instruction for fast block transfers
2. Minimizes register usage
3. Uses hardware-assisted copy operations
4. Reduces function call overhead