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minimal-printf: Disable floating point support by default
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Mbed OS should not require floating point in its base configuration.
This provides further code size savings out of the box.
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@hugueskamba
hugueskamba committed Sep 11, 2019
1 parent 8f1bf43 commit 03c484a
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Showing 2 changed files with 21 additions and 24 deletions.
2 changes: 1 addition & 1 deletion platform/mbed_lib.json
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Original file line number Diff line number Diff line change
Expand Up @@ -140,7 +140,7 @@
},
"minimal-printf-enable-floating-point": {
"help": "Enable floating point printing when using mprintf profile",
"value": true
"value": false
},
"minimal-printf-set-floating-point-max-decimals": {
"help": "Maximum number of decimals to be printed",
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43 changes: 20 additions & 23 deletions platform/source/minimal-printf/README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -41,7 +41,7 @@ Minimal printf is configured by the following parameters defined in `platform/mb
},
"minimal-printf-enable-floating-point": {
"help": "Enable floating point printing when using minimal-printf profile",
"value": true
"value": false
},
"minimal-printf-set-floating-point-max-decimals": {
"help": "Maximum number of decimals to be printed",
Expand All @@ -51,7 +51,7 @@ Minimal printf is configured by the following parameters defined in `platform/mb
}
```

By default, 64 bit integers, floating point and FILE stream printing are enabled.
By default, 64 bit integers support is enabled.

If your target does not require some options then you can override the default configuration in your application `mbed_app.json` and achieve further memory optimisation (see next section for size comparison numbers).

Expand Down Expand Up @@ -87,33 +87,30 @@ https://github.com/ARMmbed/mbed-os-example-blinky application compiled with the

Blinky application size on K64F/GCC_ARM

| | File stream | Floating point | 64 bit integers | Flash | RAM |
| - | - | - | - | - | - |
| mbed-printf | | | | 30,944 | 12,096 |
| mbed-printf | | | X | 31,084 | 12,096 |
| mbed-printf | | X | X | 33,824 | 12,096 |
| mbed-printf | X | X | X | 34,304 | 12,096 |
| std printf | X | X | X | 54,158 | 12,112 |
| | Floating point | 64 bit integers | Flash | RAM |
| - | - | - | - | - |
| mbed-printf | | | 32,972 | 11,608 |
| mbed-printf | | X | 33,116 | 11,608 |
| mbed-printf | X | X | 35,856 | 11,608 |
| std printf | X | X | 55,766 | 12,104 |

Blinky application size on K64F/ARMC6

| | File stream | Floating point | 64 bit integers | Flash | RAM |
| - | - | - | - | - | - |
| mbed-printf | | | | 31,543 | xxxxx |
| mbed-printf | | | X | 31,691 | xxxxx |
| mbed-printf | | X | X | 34,515 | xxxxx |
| mbed-printf | X | X | X | 34,647 | xxxxx |
| std printf | X | X | X | 37,458 | xxxxx |
| | Floating point | 64 bit integers | Flash | RAM |
| - | - | - | - | - |
| mbed-printf | | | 33,585 | xxxxx |
| mbed-printf | | X | 33,679 | xxxxx |
| mbed-printf | X | X | 36,525 | xxxxx |
| std printf | X | X | 39,128 | xxxxx |

Blinky application size on K64F/IAR

| | File stream | Floating point | 64 bit integers | Flash | RAM |
| - | - | - | - | - | - |
| mbed-printf | | | | 28,713 | 8,546 |
| mbed-printf | | | X | 28,853 | 8,546 |
| mbed-printf | | X | X | 30,661 | 8,546 |
| mbed-printf | X | X | X | 32,047 | 8,594 |
| std printf | X | X | X | 35,055 | 8,462 |
| | Floating point | 64 bit integers | Flash | RAM |
| - | - | - | - | - |
| mbed-printf | | | 31,439 | 8,493 |
| mbed-printf | | X | 31,579 | 8,493 |
| mbed-printf | X | X | 33,387 | 8,493 |
| std printf | X | X | 36,643 | 8,553 |

### Blinky bare metal application

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