An exercise on polyglossy: the same problem solved on multiple languages
Optimized the x86 implementation, deprecating the unnecessary use of static variables in the program.
1 file changed, 98 insertions, 96 deletions
| Status | File Name | N° Changes | Insertions | Deletions |
| Modified | Extra/x86/PROGRAM.ASM | 194 | 98 | 96 |
diff --git a/Extra/x86/PROGRAM.ASM b/Extra/x86/PROGRAM.ASM @@ -3,13 +3,6 @@ .stack 1000h .data - max dw 0 - a dw 0 - b dw 0 - sumAB dw 0 - sumA dw 0 - sumB dw 0 - sums_cache dw 25000 DUP(0) .code @@ -20,139 +13,103 @@ start: mov ds, ax call read_uint ; Retrieve user input - call cache_sums call counterexpl -read_uint: - push si - - ; Move the start of the command-line tail to `si` - mov si, ds - add si, 81h - -read_loop: - ; Read a character from the command-line tail - mov bx, [si] - - ; Jump out of the loop at the end of the first arg - cmp bx, 20h - jmp read_end - cmp bx, 0dh - jmp read_end - - ; Check if it's a numeric character - cmp bx, 30h - jb invalid_input - cmp bx, 39h - ja invalid_input - - ; Convert the character code into a decimal digit - sub bx, 30h - - ; ax = ax * 10 + bx - push cx - mov cx, 10 - mul cx - pop cx - add ax, bx - - ; Increment the pointer to the argument string and keep looping - inc si - jmp read_loop - -read_end: - mov max, ax - pop si - ret - cache_sums: - mov si, offset sums_cache + push ax ; Preserve the value of max - mov ax, max - mov bx, 2 - mul bx - mov bx, ax + mov si, offset sums_cache - mov ax, 0 + mov cx, 2 + mul cx ; ax = max * 2 cache_sums_loop: - push bx - push ax - call sum_digits - mov [si], bx + call sum_digits + mov [si], bx - pop ax add si, 2 - inc ax + dec ax - pop bx - cmp ax, bx - jb cache_sums_loop + cmp ax, 0 + ja cache_sums_loop ; while ax > 0, keep looping + + pop ax ; Restore the value of max to ax ret ; Iterate `a` from 0 to `max` +; At the start of this routine ax holds the value of max counterexpl: - mov ax, a + mov cx, 9 ; Set the devident to 9 +counterexpl_loop: call iter - inc ax - mov a, ax - cmp ax, max - jbe counterexpl + dec ax ; a -= 1 + cmp ax, 0 ; if a > 0, keep looping + ja counterexpl_loop call ok + ret ; Iterate `b` from `a` to 0 +; At the start of this routine ax holds the value of a iter: - mov ax, a - mov b, ax - + mov bx, ax iter_loop: call test_pair - dec b - mov ax, b - cmp ax, 0 + dec bx + cmp bx, 0 jae iter_loop ret +; At the start of this routine ax holds the value of a +; and bx holds the value of b test_pair: - ; Calculate S(A + B) and store it in sumAB + ; Preserve bp and sp + push bp + mov bp, sp + + sub sp, 6 ; Make room for 3 words [S(a + b), S(a) and S(b)] + push ax ; Preserve the value of a + + ; S(a + b) = sums_cache[a + b] mov si, offset sums_cache - add si, a - add si, b + add si, ax + add si, bx mov ax, [si] - mov sumAB, ax - mov ax, si + mov [bp - 6], ax - ; Calculate S(A) and store it in sumA - mov si, offset sums_cache - add si, a + ; S(a) = sums_cache[a] + sub si, bx mov ax, [si] - mov sumA, ax + mov [bp - 4], ax - ; Calculate S(B) and store it in sumB + ; S(b) = sums_cache[b] mov si, offset sums_cache - add si, b + add si, bx mov ax, [si] - mov sumB, ax + mov [bp - 2], ax + ; Store S(a + b) - S(a) - S(b) in ax + mov ax, [bp - 6] + sub ax, [bp - 4] + sub ax, [bp - 2] - ; Calculate S(a + b) - S(a) - S(b) in ax - mov ax, sumAB - sub ax, sumA - sub ax, sumB - - mov cx, 9 ; Set the devident to 9 - mov dx, 0 ; Clear the register where the rest will be stored + mov dx, 0 ; Clear the register where the rest will be stored div cx + pop ax ; Restore the value of a to ax - cmp dx, 0 + cmp dx, 0 ; if (S(a + b) - S(a) - S(b)) % 9 != 0, goto fail jne fail + ; Restore bp and sp + mov sp, bp + pop bp ret sum_digits: + push ax + mov cx, 10 ; Store the devident in cx mov bx, 0 ; Clear the register where the result will be stored sum_loop: @@ -164,6 +121,51 @@ sum_loop: ; Loop until ax equals 0 cmp ax, 0 ja sum_loop + + pop ax + ret + +; Reads the first element of the command-line tail and +; tries to convert it to an unsigned word +read_uint: + mov ax, 0 + mov cx, 10 + push si + + ; Move the start of the command-line tail to `si` + ;mov si, ds + mov si, 5eh + +read_loop: + ; Read a character from the command-line tail + mov bh, 0 + mov bl, [si] + + ; Jump out of the loop at the end of the first arg + cmp bl, ' ' + jmp read_uint_end + cmp bl, 0dh + jmp read_uint_end + + ; Check if it's a numeric character + cmp bl, 30h + jb short invalid_input + cmp bl, 39h + ja short invalid_input + + ; Convert the character code into a decimal digit + sub bx, 30h + + ; ax = ax * 10 + bx + mul cx + add ax, bx + + ; Increment the pointer to the argument string and keep looping + inc si + jmp read_loop + +read_uint_end: + pop si ret ;; Exit with exit-code 0