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Diffstat (limited to 'docs/language.md')
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1 files changed, 1 insertions, 1 deletions
diff --git a/docs/language.md b/docs/language.md index 8556c8b..42b178e 100644 --- a/docs/language.md +++ b/docs/language.md @@ -271,5 +271,5 @@ ld -e main program.o -o program The [README](../README.md) has a Docker setup with these tools. ## Some stinkies -Clobbering is your responsibility: `syscall` trashes `rcx` and `r11`, while a callee can trash any registers it touches, so nothing is saved automatically. `examples/fibonacci.hdass`, for example, keeps its counter in `r15` for this reason. Register widths must also match, meaning something like `rax = r1.8` would become `mov rax, al`, which will not assemble. Division has its own restrictions: `/` and `/=` use `idiv` through `rax:rdx`, clobbering both registers regardless of the destination, and the divisor cannot be `rax`, `rdx`, or an immediate, so it must first be placed in another register. Finally, the entry procedure has no `ret`; it should end with an exit syscall. +Clobbering is your responsibility: `syscall` trashes `rcx` and `r11`, while a callee can trash any registers it touches, so nothing is saved automatically. `examples/fibonacci.hdass`, for example, keeps its counter in `r15` for this reason. Register widths must also match, meaning something like `rax = r1.8` would become `mov rax, al`, which will not assemble. Division clobbers extra registers: `/` `%` and their `=` forms use `idiv` through `rax:rdx`, so both are overwritten regardless of the destination. The divisor can be anything — a register, a constant, or an immediate — but an immediate or an `rax`/`rdx` divisor is first copied into `r11`, so those also clobber `r11`. Finally, the entry procedure has no `ret`; it should end with an exit syscall. |