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On Thursday, 27 March 2025 at 17:31:54 UTC, Walter Bright wrote:
>On 3/27/2025 9:15 AM, Walter Bright wrote:
>Can also just scale up the long arithmetic asm routines that implement 32 bit arithmetic on the 16 bit x86.
https://github.com/DigitalMars/dmc/blob/master/src/CORE16/LMATH.ASM
here is what deepseek came up with:
To convert the provided x86 assembly code for 32-bit arithmetic operations to AARCH64, we leverage ARM's efficient instruction set for multiplication, division, and comparison. Here's the equivalent implementation:
.section .text
.align 2
.global _LMUL@
_LMUL@:
// Unsigned 32-bit multiply, result 64-bit in x0
umull x0, w0, w1
ret
.global _ULDIV@
_ULDIV@:
// Check for division by zero
cmp w1, #0
beq div0_unsigned
// Perform unsigned division
udiv w2, w0, w1 // Quotient in w2
msub w3, w2, w1, w0 // Remainder in w3
mov w0, w2 // Return quotient
mov w1, w3 // Return remainder
ret
div0_unsigned:
// Handle division by zero: return (0xFFFFFFFF, 0)
mov w0, #-1
mov w1, #0
ret
.global _LDIV@
_LDIV@:
// Check for division by zero
cmp w1, #0
beq div0_signed
// Perform signed division
sdiv w2, w0, w1 // Quotient in w2
msub w3, w2, w1, w0 // Remainder in w3
mov w0, w2 // Return quotient
mov w1, w3 // Return remainder
ret
div0_signed:
// Handle division by zero: return (-1, 0)
mov w0, #-1
mov w1, #0
ret
.global _LCMP@
_LCMP@:
// Compare two signed 32-bit values
cmp w0, w1
b.gt .greater
b.lt .less
mov w0, #0 // Equal case
ret
.greater:
mov w0, #1 // Greater than
ret
.less:
mov w0, #-1 // Less than
ret
